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RSS2013 Vol. 32, No. 2
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2013, 32(2): 157-159.
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Abstract:
Numerical simulation of metal machining based on FEM has great significance for both improving the ma-chining technology and enhancing surface integrity and realizing high efficiency machining. In this paper,in orderto the simulation demand of TB6 titanium alloy machining, the experiment for getting stress-strain curves at differenttemperature and strain rate has been designed and carried out with universal testing machine, Gleeble thermal simu-lator and Hopkinson bar testing apparatus. Based on the experimental data, the constitutive relationship of TB6 tita-nium alloy has been established.
Numerical simulation of metal machining based on FEM has great significance for both improving the ma-chining technology and enhancing surface integrity and realizing high efficiency machining. In this paper,in orderto the simulation demand of TB6 titanium alloy machining, the experiment for getting stress-strain curves at differenttemperature and strain rate has been designed and carried out with universal testing machine, Gleeble thermal simu-lator and Hopkinson bar testing apparatus. Based on the experimental data, the constitutive relationship of TB6 tita-nium alloy has been established.
2013, 32(2): 160-163.
Abstract:
Torque converter is a key component of hydro-mechanical transmission system. To improve the workingefficiency of hydro-mechanical transmission system,the lockup and unlock control strategy of torque converter wasdesigned. The dynamic model for lockable torque converter was established,and three types of its working condi-tions,including hydraulic working condition,frictional working condition and mechanical working condition,wereanalyzed,based on the present simulation model for torque converter. The model of lockable torque converter wasapplied to the powertrain system model of a certain tracked engineer vehicle. Under the control strategy of dynamicgear shift,the simulation model was computed from 2 nd gear and upshifted to 6 th gear. The simulation result indi-cates the lockup and unlock control strategy is correct and valid.
Torque converter is a key component of hydro-mechanical transmission system. To improve the workingefficiency of hydro-mechanical transmission system,the lockup and unlock control strategy of torque converter wasdesigned. The dynamic model for lockable torque converter was established,and three types of its working condi-tions,including hydraulic working condition,frictional working condition and mechanical working condition,wereanalyzed,based on the present simulation model for torque converter. The model of lockable torque converter wasapplied to the powertrain system model of a certain tracked engineer vehicle. Under the control strategy of dynamicgear shift,the simulation model was computed from 2 nd gear and upshifted to 6 th gear. The simulation result indi-cates the lockup and unlock control strategy is correct and valid.
2013, 32(2): 164-169.
Abstract:
A probabilistic fatigue life prediction method for notched specimens was established based on the wea-kest-link theory and Weibull fatigue life distribution of smooth specimen. A Weibull equivalent stress was derivedand fatigue failure probability for notched specimen was formulated based on the weakest-link theory and fatiguestrength distribution of smooth specimen. According to the relationship between the Walker equivalent stress andthe characteristic fatigue life,the characteristic life of notched specimen can be calculated based on the Weibull e-quivalent stress. Finally the life distribution of notched specimens can be obtained based on the fatigue life distribu-tion of smooth specimen. This method was evaluated by the probabilistic fatigue life prediction of TC4 alloy notchedspecimens and the prediction result was compared with the local stress-strain method. The result shows that the lo-cal stress-strain method was very conservative,the method presented in this paper can predict more accurately. Thepredicted life with 50% failure rate agrees well with the test mean tested life of TC4 alloy notched specimens. Thepredicted life with 10% and 90% failure rate are mostly within the scatter band of 2 compared to the test mean life.
A probabilistic fatigue life prediction method for notched specimens was established based on the wea-kest-link theory and Weibull fatigue life distribution of smooth specimen. A Weibull equivalent stress was derivedand fatigue failure probability for notched specimen was formulated based on the weakest-link theory and fatiguestrength distribution of smooth specimen. According to the relationship between the Walker equivalent stress andthe characteristic fatigue life,the characteristic life of notched specimen can be calculated based on the Weibull e-quivalent stress. Finally the life distribution of notched specimens can be obtained based on the fatigue life distribu-tion of smooth specimen. This method was evaluated by the probabilistic fatigue life prediction of TC4 alloy notchedspecimens and the prediction result was compared with the local stress-strain method. The result shows that the lo-cal stress-strain method was very conservative,the method presented in this paper can predict more accurately. Thepredicted life with 50% failure rate agrees well with the test mean tested life of TC4 alloy notched specimens. Thepredicted life with 10% and 90% failure rate are mostly within the scatter band of 2 compared to the test mean life.
2013, 32(2): 170-177.
Abstract:
This paper presents the grinding control method and the grinding wheel wear compensation algorithms bymeasuring the height of the saw bit. Before and after processing the saw bit,the CNC system obtains the height ofthe saw bit by applying the displacement sensor,which helps to obtain a series of grinding parameters and controlthe grinding process. The feeder manipulator controlled by an independent type PLC completes the feeding andtransporting actions. By combining of the displacement sensor with the feeder manipulator,the grinding machinecompletes the grinding work automatically. The partially parallel running between the feeder manipulator action andthe saw grinding work saves a lot of time and achieves the objectives of high accuracy,high efficiency and easy op-eration.
This paper presents the grinding control method and the grinding wheel wear compensation algorithms bymeasuring the height of the saw bit. Before and after processing the saw bit,the CNC system obtains the height ofthe saw bit by applying the displacement sensor,which helps to obtain a series of grinding parameters and controlthe grinding process. The feeder manipulator controlled by an independent type PLC completes the feeding andtransporting actions. By combining of the displacement sensor with the feeder manipulator,the grinding machinecompletes the grinding work automatically. The partially parallel running between the feeder manipulator action andthe saw grinding work saves a lot of time and achieves the objectives of high accuracy,high efficiency and easy op-eration.
2013, 32(2): 178-183.
Abstract:
In order to investigate the cutting effect of ceramic tile calibrating machine,the structure and workingprinciple of the calibrating machine were analyzed,meanwhile the mathematical model for the cutting depth of ce-ramic tile was established. The influence factors of cutting depth were analyzed,the effectiveness of the model wasverified by experiments. According to the results of theoretical and experimental results,it is concluded that thecombination of big diameter cylinder,low feed rate of ceramic tile and deeper cutting depth can enhance the cuttingefficiency of ceramic tile.
In order to investigate the cutting effect of ceramic tile calibrating machine,the structure and workingprinciple of the calibrating machine were analyzed,meanwhile the mathematical model for the cutting depth of ce-ramic tile was established. The influence factors of cutting depth were analyzed,the effectiveness of the model wasverified by experiments. According to the results of theoretical and experimental results,it is concluded that thecombination of big diameter cylinder,low feed rate of ceramic tile and deeper cutting depth can enhance the cuttingefficiency of ceramic tile.
2013, 32(2): 184-187.
Abstract:
Based on the experimental results of temperature field,the outermost average temperature of coking fur-nace wall is 40. 42 ℃,which results in a great loss of heat and not meeting project needs. According to the heattransfer principle and Galerkin method,the mathematical model of the furnace wall was established. Then tempera-ture values at an interface were obtained without optimization. Comparing with the experimental results, the theoret-ical values from mathematical model are in a good agreement with the experimental. It shows that the mathematicalmodel is reliable. When the total thickness of the furnace wall is constant, in order to obtain the outermost tempera-ture less than 30 ℃,the most reasonable structure parameters of coking furnace wall are received on the basis ofthe mathematical model in the engineering requirements.
Based on the experimental results of temperature field,the outermost average temperature of coking fur-nace wall is 40. 42 ℃,which results in a great loss of heat and not meeting project needs. According to the heattransfer principle and Galerkin method,the mathematical model of the furnace wall was established. Then tempera-ture values at an interface were obtained without optimization. Comparing with the experimental results, the theoret-ical values from mathematical model are in a good agreement with the experimental. It shows that the mathematicalmodel is reliable. When the total thickness of the furnace wall is constant, in order to obtain the outermost tempera-ture less than 30 ℃,the most reasonable structure parameters of coking furnace wall are received on the basis ofthe mathematical model in the engineering requirements.
2013, 32(2): 188-191.
Abstract:
The mathematical relationship between the two models which are frequently used to describe visco-elasticmaterial is established by means of the interpolation method of linear equation group. This method realized thetransformation between the Kelvin model of fractional derivative and the generalized Maxwell model. As the de-scribed above,with MATLAB,the Kelvin model in the form of fractional derivative which can accurately describedthe relaxation changing patterns of BTG plastic alloy is firstly established with the experimental. Then,the parame-ter in Maxwell model for the material can be got by the method above. The result shows that the relaxation moduluscurve which transformed by Kelvin model of fractional derivative fit the experimental data very well.
The mathematical relationship between the two models which are frequently used to describe visco-elasticmaterial is established by means of the interpolation method of linear equation group. This method realized thetransformation between the Kelvin model of fractional derivative and the generalized Maxwell model. As the de-scribed above,with MATLAB,the Kelvin model in the form of fractional derivative which can accurately describedthe relaxation changing patterns of BTG plastic alloy is firstly established with the experimental. Then,the parame-ter in Maxwell model for the material can be got by the method above. The result shows that the relaxation moduluscurve which transformed by Kelvin model of fractional derivative fit the experimental data very well.
2013, 32(2): 192-197.
Abstract:
It is a basic way to realize the ideal composite braking system and improve the efficiency of the brakingenergy recovery on the premise of meeting the braking stability requirements and ECE regulations etc by increasingthe braking force proportion on the drive shaft of electric vehicles as much as possible, even single axis braking withthe regenerative braking torque. The driving type and axle load distribution of the electric vehicles will influence thesingle axial braking stability of the ramp driving. And four situations were analyzed including single axial brake inuphill and downhill process involving lock,longitudinal turn and longitudinal sliding etc. critical conditions. Andstability conditions of the single axle ramp braking and regenerative braking limitation were achieved,which wouldprovide a theory reference to formulate the coordinated control algorithm of the composite braking system.
It is a basic way to realize the ideal composite braking system and improve the efficiency of the brakingenergy recovery on the premise of meeting the braking stability requirements and ECE regulations etc by increasingthe braking force proportion on the drive shaft of electric vehicles as much as possible, even single axis braking withthe regenerative braking torque. The driving type and axle load distribution of the electric vehicles will influence thesingle axial braking stability of the ramp driving. And four situations were analyzed including single axial brake inuphill and downhill process involving lock,longitudinal turn and longitudinal sliding etc. critical conditions. Andstability conditions of the single axle ramp braking and regenerative braking limitation were achieved,which wouldprovide a theory reference to formulate the coordinated control algorithm of the composite braking system.
2013, 32(2): 198-202.
Abstract:
The effects of an imperfect horizontal strut of two-layer fully triangular grid material on the stress distri-bution are investigated analytically and numerically. Based on the structural variation method,an analytical equiva-lent model was proposed to quantify the influence of the imperfect strut on the stress distribution of the structure.The results show that the influence is independent with the imperfection degree and the stresses caused by the im-perfect strut are decaying in a fixed rate that is equal to the Saint-Venant decay rate obtained by the transfer matrixmethod. The finite element simulations are used to validate the predictions.
The effects of an imperfect horizontal strut of two-layer fully triangular grid material on the stress distri-bution are investigated analytically and numerically. Based on the structural variation method,an analytical equiva-lent model was proposed to quantify the influence of the imperfect strut on the stress distribution of the structure.The results show that the influence is independent with the imperfection degree and the stresses caused by the im-perfect strut are decaying in a fixed rate that is equal to the Saint-Venant decay rate obtained by the transfer matrixmethod. The finite element simulations are used to validate the predictions.
2013, 32(2): 203-208.
Abstract:
Electron cyclotron resonance ion thruster is a type of static electric thruster,and it has the advantages ofhigh specific impulse,electrodeless and high durability,which make the thruster competitive in the applications ofdeep space probe and long life satellite. The discharge chamber is the key component of electron cyclotron reso-nance ion thruster. Within the discharge chamber,applied magnetic field,microwave and plasma are coupled to-gether. It is important to understand the plasma parameters for the optimization of the chamber structure and its per-formances. At the assumption of unmagnetized ions in the chamber and with Langmuir probe,the electron tempera-ture and ion number density are diagnosed directly. The results show that at argon mass flow rate of 3 sccm and 8sccm,and the output power of 10 W and 34 W,the electron temperature and ion density are diagnosed from 1 eVto 6. 8 eV and 2 �0 16/m3to 2. 8 �017 /m3respectively.
Electron cyclotron resonance ion thruster is a type of static electric thruster,and it has the advantages ofhigh specific impulse,electrodeless and high durability,which make the thruster competitive in the applications ofdeep space probe and long life satellite. The discharge chamber is the key component of electron cyclotron reso-nance ion thruster. Within the discharge chamber,applied magnetic field,microwave and plasma are coupled to-gether. It is important to understand the plasma parameters for the optimization of the chamber structure and its per-formances. At the assumption of unmagnetized ions in the chamber and with Langmuir probe,the electron tempera-ture and ion number density are diagnosed directly. The results show that at argon mass flow rate of 3 sccm and 8sccm,and the output power of 10 W and 34 W,the electron temperature and ion density are diagnosed from 1 eVto 6. 8 eV and 2 �0 16/m3to 2. 8 �017 /m3respectively.
2013, 32(2): 209-212.
Abstract:
During the loading of electromagnetic impact,a panel coil is not only a carrier for electric energy to betransformed into magnetic energy but also a key unit makes a blank plastically deformed. This paper introduces thebasic principle of electromagnetic drive of the panel coil simulates the influence of its geometric parameters on axialelectromagnetic force,probes into the distribution of the electromagnetic force on the drive and the impact of thepanel coil on the efficiency of the equipment power use. The result demonstrates that with the increase of turns,theaxial electromagnetic force increases exponentially; with the increase of the distance between turns,the axial elec-tromagnetic force decreases exponentially and with the increase of inner radius,diminishes almost exponentially.The strongest electromagnetic force is at the region 2/3 away from the symmetrical axis; the decrease of inductancevalue helps improve forming efficiency.
During the loading of electromagnetic impact,a panel coil is not only a carrier for electric energy to betransformed into magnetic energy but also a key unit makes a blank plastically deformed. This paper introduces thebasic principle of electromagnetic drive of the panel coil simulates the influence of its geometric parameters on axialelectromagnetic force,probes into the distribution of the electromagnetic force on the drive and the impact of thepanel coil on the efficiency of the equipment power use. The result demonstrates that with the increase of turns,theaxial electromagnetic force increases exponentially; with the increase of the distance between turns,the axial elec-tromagnetic force decreases exponentially and with the increase of inner radius,diminishes almost exponentially.The strongest electromagnetic force is at the region 2/3 away from the symmetrical axis; the decrease of inductancevalue helps improve forming efficiency.
2013, 32(2): 213-216.
Abstract:
Aiming at the product assembly guidance based on in augmented reality using natural features of parts,we propose the virtual-real assembly scene registration and integration method BRIEF algorithm. With the algorithmthe image's natural features of parts for assembly were extracted and the descriptors of their features were created.The descriptors are matched through the Hamming distance during the assembly guidance process to realize thescenery registration. Meanwhile,the virtual assembly information was superposed into the actual assembly scene toguide the assembly process. Experimental results show that the registration method that uses the BRIEF algorithmhas better robustness and real-time performance, and can be applied to product assembly guidance process based onaugmented reality.
Aiming at the product assembly guidance based on in augmented reality using natural features of parts,we propose the virtual-real assembly scene registration and integration method BRIEF algorithm. With the algorithmthe image's natural features of parts for assembly were extracted and the descriptors of their features were created.The descriptors are matched through the Hamming distance during the assembly guidance process to realize thescenery registration. Meanwhile,the virtual assembly information was superposed into the actual assembly scene toguide the assembly process. Experimental results show that the registration method that uses the BRIEF algorithmhas better robustness and real-time performance, and can be applied to product assembly guidance process based onaugmented reality.
2013, 32(2): 217-220.
Abstract:
Steady and unsteady three-dimensional viscous flows are calculated to obtain flow fields under various operat-ing conditions for two-level highly loaded transonic forward-speep rotors and to advance the understanding of the flowfield near tip regions. The study shows that with the forward-swept rotor,the tip clearance vortex does not break downeven under the stalled condition. A low momentum area originating from the endwall boundary layer prevents incomingflow from passing through the pressure side of the passage and initiates stall inception. With the backsweep rotor,thecore tip clearance vortex breaks down just like when a conventional rotor does near the stalled condition.
Steady and unsteady three-dimensional viscous flows are calculated to obtain flow fields under various operat-ing conditions for two-level highly loaded transonic forward-speep rotors and to advance the understanding of the flowfield near tip regions. The study shows that with the forward-swept rotor,the tip clearance vortex does not break downeven under the stalled condition. A low momentum area originating from the endwall boundary layer prevents incomingflow from passing through the pressure side of the passage and initiates stall inception. With the backsweep rotor,thecore tip clearance vortex breaks down just like when a conventional rotor does near the stalled condition.
2013, 32(2): 221-224.
Abstract:
Ultrasonic vibration was superimposed into the compression process of AZ31 Magnesium alloy, 6061 and7075 aluminum alloys, in order to obtain the effects of ultrasonic vibration on the plastic deformation behavior, suchas,flow stress,rupture characteristics and formed surface in the compression process of the light alloys. It wasfound that both Volume Effect and Surface Effect have influenced on the compression process after ultrasonic vibra-tion superimposed; the yield stress and flow stress of the material decreased,and the decreasing amount is relatedto the material property, 6061 aluminum alloy is more sensitive to the vibrating effect; for AZ31 magnesium alloy,with the increasing of vibration amplitude,the hardening in Volume Effect becomes dominant. Furthermore,vibra-tion can improve the quality of formed surface.
Ultrasonic vibration was superimposed into the compression process of AZ31 Magnesium alloy, 6061 and7075 aluminum alloys, in order to obtain the effects of ultrasonic vibration on the plastic deformation behavior, suchas,flow stress,rupture characteristics and formed surface in the compression process of the light alloys. It wasfound that both Volume Effect and Surface Effect have influenced on the compression process after ultrasonic vibra-tion superimposed; the yield stress and flow stress of the material decreased,and the decreasing amount is relatedto the material property, 6061 aluminum alloy is more sensitive to the vibrating effect; for AZ31 magnesium alloy,with the increasing of vibration amplitude,the hardening in Volume Effect becomes dominant. Furthermore,vibra-tion can improve the quality of formed surface.
2013, 32(2): 225-230.
Abstract:
The nanoscale stick-slip friction process of a rigid hemispherical tip on a single crystal copper texturesurface was investigated by using molecular dynamics simulation. The effects of texture shape and texture depth onthe characteristics of stick-slip friction under different texture densities were studied. The comparative analysis ofsliding friction force and substrate's deformation with different texture parameters reveals the effects of these param-eters on the stick-slip friction process. The simulation results show that the sliding friction force on the square pillartexture surface is less than that on the groove texture surface with the same texture density; compared with thegroove texture surface,the square pillar texture surface's structural stability is poor,but the latter's structural sta-bility is strengthened while its texture density increases; when the surface texture density is constant,the slidingfriction force on the groove texture surface decreases with the increasing of the texture depth.
The nanoscale stick-slip friction process of a rigid hemispherical tip on a single crystal copper texturesurface was investigated by using molecular dynamics simulation. The effects of texture shape and texture depth onthe characteristics of stick-slip friction under different texture densities were studied. The comparative analysis ofsliding friction force and substrate's deformation with different texture parameters reveals the effects of these param-eters on the stick-slip friction process. The simulation results show that the sliding friction force on the square pillartexture surface is less than that on the groove texture surface with the same texture density; compared with thegroove texture surface,the square pillar texture surface's structural stability is poor,but the latter's structural sta-bility is strengthened while its texture density increases; when the surface texture density is constant,the slidingfriction force on the groove texture surface decreases with the increasing of the texture depth.
2013, 32(2): 231-234.
Abstract:
Aiming to optimize the front wheel alignment parameters of Formula SAE(FSAE) racing car,the simu-lation model of double wishbone independent suspension of FSAE racing car was established based on ADAMS/Carmodule,and the front wheel alignment parameters were simulated and analyzed. Then the variables of the designparameters and design objectives were determined by using ADAMS/Insight module,and the influence factors onthe selected design goal were also analyzed. Afterwards the front suspension simulation model was modified accord-ing to the optimization results,and the front wheel alignment parameters were simulated and analyzed again. Theresult shows that when racing wheels bounce up and down,the front wheel alignment parameters vary within a rea-sonable range,in which meets the suspension design requirements of racing car,and the suspension performance ofracing car is significantly improved.
Aiming to optimize the front wheel alignment parameters of Formula SAE(FSAE) racing car,the simu-lation model of double wishbone independent suspension of FSAE racing car was established based on ADAMS/Carmodule,and the front wheel alignment parameters were simulated and analyzed. Then the variables of the designparameters and design objectives were determined by using ADAMS/Insight module,and the influence factors onthe selected design goal were also analyzed. Afterwards the front suspension simulation model was modified accord-ing to the optimization results,and the front wheel alignment parameters were simulated and analyzed again. Theresult shows that when racing wheels bounce up and down,the front wheel alignment parameters vary within a rea-sonable range,in which meets the suspension design requirements of racing car,and the suspension performance ofracing car is significantly improved.
2013, 32(2): 235-239.
Abstract:
In this paper,the strain damage model of composite laminate is proposed to conside the fracture,matrixcracking,fiber tension and fiber compression caused by the impact. In the numerical simulation,the user subrou-tine VUMAT and the cohesive model in Abaqus software are chosen to describe the damage and delamination of theinterfaces between different composite laminates. The low-velocity impact for composite laminates under differentamount of is simulated. The simulation results show that the simulated delamination damage area,contact force,the maximum deflection of the impactor and the dent depth agree well with experimental results.
In this paper,the strain damage model of composite laminate is proposed to conside the fracture,matrixcracking,fiber tension and fiber compression caused by the impact. In the numerical simulation,the user subrou-tine VUMAT and the cohesive model in Abaqus software are chosen to describe the damage and delamination of theinterfaces between different composite laminates. The low-velocity impact for composite laminates under differentamount of is simulated. The simulation results show that the simulated delamination damage area,contact force,the maximum deflection of the impactor and the dent depth agree well with experimental results.
2013, 32(2): 240-245.
Abstract:
A novel method using circuit model to predict the pin load distribution of multiple-bolted joints in com-posite laminate was presented. The load,flexibility and deformation of the multiple-bolted joints were treated asequivalent to the current,resistance and voltage of the circuit model respectively. Based on the above assumptions,Hooke's law and the deformation compatibility equation in the original mechanics model were transformed intoOhm's law and voltage balance equation in the new circuit model. This method changed the complex model of mul-tiple bolted-joints in composite laminate into a simple circuit model which consists of some series circuits and paral-lel circuits. The analysis of the new circuit model had led to n －1 independent voltage balance equations and a cur-rent balance equation. With the n －1 equations,each bolt's current which is equivalent to its load can be calculat-ed. With the circuit model,power sources which were added as required in some subcircuits can also simulate theclearance or interference in multiple-bolted joints. Compared with the results of the multiple bolted-joints compositelaminate test,this new method can estimate well the load distribution of a multiple-bolted joints.
A novel method using circuit model to predict the pin load distribution of multiple-bolted joints in com-posite laminate was presented. The load,flexibility and deformation of the multiple-bolted joints were treated asequivalent to the current,resistance and voltage of the circuit model respectively. Based on the above assumptions,Hooke's law and the deformation compatibility equation in the original mechanics model were transformed intoOhm's law and voltage balance equation in the new circuit model. This method changed the complex model of mul-tiple bolted-joints in composite laminate into a simple circuit model which consists of some series circuits and paral-lel circuits. The analysis of the new circuit model had led to n －1 independent voltage balance equations and a cur-rent balance equation. With the n －1 equations,each bolt's current which is equivalent to its load can be calculat-ed. With the circuit model,power sources which were added as required in some subcircuits can also simulate theclearance or interference in multiple-bolted joints. Compared with the results of the multiple bolted-joints compositelaminate test,this new method can estimate well the load distribution of a multiple-bolted joints.
2013, 32(2): 246-251.
Abstract:
A kind of dynamic analysis and design method of high-speed slider-cam cigarette separation system waspresented. Based on the dynamic model of slider system, the cam controlling movement of slider was designed, andthe stiffness of locking spring was calculated as well. Based on the structural finite element model, the modal analy-sis of cam was presented and the results verified the rationality of the design of cam; as a result,the system reso-nance was avoided. Based on the virtual prototyping technology,the system dynamic performance analysis showedthat the method of analysis and design can reflect the characteristics of high-speed slider-cam separation systemwell,realize accurate and reliable separation movement,and also avoid the occurrence of such phenomena as sli-der's jumping,excessive wear of moving parts while reducing the power consumption of system.
A kind of dynamic analysis and design method of high-speed slider-cam cigarette separation system waspresented. Based on the dynamic model of slider system, the cam controlling movement of slider was designed, andthe stiffness of locking spring was calculated as well. Based on the structural finite element model, the modal analy-sis of cam was presented and the results verified the rationality of the design of cam; as a result,the system reso-nance was avoided. Based on the virtual prototyping technology,the system dynamic performance analysis showedthat the method of analysis and design can reflect the characteristics of high-speed slider-cam separation systemwell,realize accurate and reliable separation movement,and also avoid the occurrence of such phenomena as sli-der's jumping,excessive wear of moving parts while reducing the power consumption of system.
2013, 32(2): 252-256.
Abstract:
The structure and transmission principle of Filtering Gear Reducer (FGR) with small tooth numberdifference was introduced. Based on the geometry size related differential model,the transmission ratio formula ofthe reducer with considering the component eccentricity including eccentric shaft,dual gear and fixed gear was de-rived,and transmission error curves were obtained by applying the numerical solution for differential equations. Thetransmission error test on the reducer was carried out. The method was used for the eccentric transmission calcula-tion in this paper was verified by the test results. Meanwhile,the test results illuminated that the eccentric errorstudy played an important role in the transmission error study of filtering gear reducer.
The structure and transmission principle of Filtering Gear Reducer (FGR) with small tooth numberdifference was introduced. Based on the geometry size related differential model,the transmission ratio formula ofthe reducer with considering the component eccentricity including eccentric shaft,dual gear and fixed gear was de-rived,and transmission error curves were obtained by applying the numerical solution for differential equations. Thetransmission error test on the reducer was carried out. The method was used for the eccentric transmission calcula-tion in this paper was verified by the test results. Meanwhile,the test results illuminated that the eccentric errorstudy played an important role in the transmission error study of filtering gear reducer.
2013, 32(2): 257-262.
Abstract:
The corrugated paperboard cushion-mass system was used to simulate the real packaging. Dynamic proper-ties model of the corrugated paperboard excited by shock load was obtained with viscoelasticity of corrugated paper-board taken into account. The free response data were expressed as the sum of complex exponentials by Laplace anal-ysis,and the poles and residues of free response data were identified by Prony method. An experimental system wasset up to record the response of corrugated paperboard cushion-mass system to base shock excitation. The parametersof the model were identified under different load conditions. The rounded impulse function was used to simulate theshock excitation and the acceleration response of the corrugated paperboard cushion-mass system was deduced.
The corrugated paperboard cushion-mass system was used to simulate the real packaging. Dynamic proper-ties model of the corrugated paperboard excited by shock load was obtained with viscoelasticity of corrugated paper-board taken into account. The free response data were expressed as the sum of complex exponentials by Laplace anal-ysis,and the poles and residues of free response data were identified by Prony method. An experimental system wasset up to record the response of corrugated paperboard cushion-mass system to base shock excitation. The parametersof the model were identified under different load conditions. The rounded impulse function was used to simulate theshock excitation and the acceleration response of the corrugated paperboard cushion-mass system was deduced.
2013, 32(2): 263-268.
Abstract:
The paper explored the power matching method for a parallel hybrid hydraulic excavator,some middle-sized hydraulic excavators' parallel hybrid system and a comprehensive control strategy based on division of workstate have been designed. Engine, battery set, hydraulic system and working plant have been built by using AMES-im,a simulation model of the hybrid system has been built too. Simulation results show that the power-matchingsystem and the control strategy can not only stabilize the engine operating point but also manage and protect the bat-tery set effectively with much better power performance indicators and energy saving indicators.
The paper explored the power matching method for a parallel hybrid hydraulic excavator,some middle-sized hydraulic excavators' parallel hybrid system and a comprehensive control strategy based on division of workstate have been designed. Engine, battery set, hydraulic system and working plant have been built by using AMES-im,a simulation model of the hybrid system has been built too. Simulation results show that the power-matchingsystem and the control strategy can not only stabilize the engine operating point but also manage and protect the bat-tery set effectively with much better power performance indicators and energy saving indicators.
2013, 32(2): 269-273.
Abstract:
The original crashworthiness was assessed by FEM analysis,and the energy absorption of each componentwas obtained. The method for improving the energy absorption characteristics was proposed. The simulation resultsshow our method is effective. The reason is that some structural details which affect the impact response were lost dur-ing modeling. The analysis model was modified,and the results show good agreement with simulation results.
The original crashworthiness was assessed by FEM analysis,and the energy absorption of each componentwas obtained. The method for improving the energy absorption characteristics was proposed. The simulation resultsshow our method is effective. The reason is that some structural details which affect the impact response were lost dur-ing modeling. The analysis model was modified,and the results show good agreement with simulation results.
2013, 32(2): 274-278.
Abstract:
The specific impact of residual stresses in aluminum-alloy engine cylinder head on crack forming was an-alyzed,while adopting the blind-hole method to measure the level and distribution of the residual stresses in thecracking areas and some other sensitive parts of three groups. Considering cylinder head's complex structure andthe position of the measuring points,the processes of drilling blind holes and milling the pipelines and their sideplates were conducted by a milling and drilling machine in this study. The time-domain curves of strain at themeasuring points were recorded by a 30-channel strain gauge (DRA-30A) during stress releasing in the processesof drilling and milling. The test results showed that the primary cause of cracks in the cylinder head is,that the re-sidual stresses in the pipelines is mainly compressive stress but in the top surface of the lower part it is tensilestress. The highest possible area of forming crack is in Point 4, and the most obvious tensile effect on the lower partresulted from the pipeline in Point 7. The structure design and processing technology of Group B90 are the mostreasonable in all three groups. According to the test results and research conclusion,the new cylinder head canmeet the design requirements after improving the structure and processing technology.
The specific impact of residual stresses in aluminum-alloy engine cylinder head on crack forming was an-alyzed,while adopting the blind-hole method to measure the level and distribution of the residual stresses in thecracking areas and some other sensitive parts of three groups. Considering cylinder head's complex structure andthe position of the measuring points,the processes of drilling blind holes and milling the pipelines and their sideplates were conducted by a milling and drilling machine in this study. The time-domain curves of strain at themeasuring points were recorded by a 30-channel strain gauge (DRA-30A) during stress releasing in the processesof drilling and milling. The test results showed that the primary cause of cracks in the cylinder head is,that the re-sidual stresses in the pipelines is mainly compressive stress but in the top surface of the lower part it is tensilestress. The highest possible area of forming crack is in Point 4, and the most obvious tensile effect on the lower partresulted from the pipeline in Point 7. The structure design and processing technology of Group B90 are the mostreasonable in all three groups. According to the test results and research conclusion,the new cylinder head canmeet the design requirements after improving the structure and processing technology.
2013, 32(2): 279-284.
Abstract:
This paper researches how to establish the load spectrum for motorized spindle reliability test,which ba-ses on investigating and collecting the milling technology and data of the domestic 170XD30 milling motorized spin-dle. Firstly,the sample data of the motorized spindle's load spectrum was sorted out after analyzing and calculatingthe relative milling data. In addition,the frequency distribution point map and cumulative frequency distributionpoint map of the milling motorized spindle's load were drawn and the overall distribution model and parameter esti-mation were initially determined. Finally,it conducted a test of distribution fit by using K-S test method,builtedthe distribution model and the five-test load spectrum of the milling motorized spindle.
This paper researches how to establish the load spectrum for motorized spindle reliability test,which ba-ses on investigating and collecting the milling technology and data of the domestic 170XD30 milling motorized spin-dle. Firstly,the sample data of the motorized spindle's load spectrum was sorted out after analyzing and calculatingthe relative milling data. In addition,the frequency distribution point map and cumulative frequency distributionpoint map of the milling motorized spindle's load were drawn and the overall distribution model and parameter esti-mation were initially determined. Finally,it conducted a test of distribution fit by using K-S test method,builtedthe distribution model and the five-test load spectrum of the milling motorized spindle.
2013, 32(2): 285-288.
Abstract:
Based on the olfactory positioning theory,combined with the mobile robot technology,a kind of wheeledactive olfaction robot system that can complete the gas source localization autonomously was designed. The robotsystem uses the Freescale Semiconductor company's 16-bit MCU (MC9S12XDT512) as the core controller,usingthe gas sensor array as a path identification unit,combined with the wheeled mobile platform,using the zigzag con-trol algorithm to control the robot to complete the gas source localization. The robot system was tested under steadywind condition to locate the ethanol gas source. With 15 m as the start distance,and after 10 times locating,theerror is less than 5% and the experimental results show that the mobile robot system can locate gas sources.
Based on the olfactory positioning theory,combined with the mobile robot technology,a kind of wheeledactive olfaction robot system that can complete the gas source localization autonomously was designed. The robotsystem uses the Freescale Semiconductor company's 16-bit MCU (MC9S12XDT512) as the core controller,usingthe gas sensor array as a path identification unit,combined with the wheeled mobile platform,using the zigzag con-trol algorithm to control the robot to complete the gas source localization. The robot system was tested under steadywind condition to locate the ethanol gas source. With 15 m as the start distance,and after 10 times locating,theerror is less than 5% and the experimental results show that the mobile robot system can locate gas sources.
2013, 32(2): 289-293.
Abstract:
Von Mises criterion was applied to convert multiaxial stress into uniaxial one; the multiaxial stress re-sponse vibration fatigue life prediction method was proposed based on the power spectral input and time domain in-put. The time domain input method was found more complete than the power spectral input method,for the phaseinteraction of stresses did not drop out. Generally,excitatory input is expressed in the form of power spectral densi-ty,while this paper translated the input power spectral into time domain by Monte-Carlo simulation method,andthen the fatigue life was calculated in time domain input method. It guarantees that the phase information of VonMises stress has the physical designation,which offers the guidance for the accurate life prediction of multiaxialstress response and the acoustic fatigue experiment.
Von Mises criterion was applied to convert multiaxial stress into uniaxial one; the multiaxial stress re-sponse vibration fatigue life prediction method was proposed based on the power spectral input and time domain in-put. The time domain input method was found more complete than the power spectral input method,for the phaseinteraction of stresses did not drop out. Generally,excitatory input is expressed in the form of power spectral densi-ty,while this paper translated the input power spectral into time domain by Monte-Carlo simulation method,andthen the fatigue life was calculated in time domain input method. It guarantees that the phase information of VonMises stress has the physical designation,which offers the guidance for the accurate life prediction of multiaxialstress response and the acoustic fatigue experiment.
2013, 32(2): 294-299.
Abstract:
The carrying capacity of super-modulus rack and pinion is a key factor which affects security and relia-bility of a jacking systems. Main partameters which affect the strength of rack and pinion in a jacking system wasanalyzed. According to supper-modulus involute cylindrical gears used in rack and pinion jacking system of a windpower installation vessel. Finite element analysis model of rack and pinion was built; pinion profile shift x,pres-sure angle α,addendum coefficient haf*,modulem and width ofrack affect contact strength and bending strength of rack and pinion were studied with the FEA. The study resultsshow that every parameter has a large influence on the carrying capacity of rack and pinion,but their degrees of in-fluence are different.
The carrying capacity of super-modulus rack and pinion is a key factor which affects security and relia-bility of a jacking systems. Main partameters which affect the strength of rack and pinion in a jacking system wasanalyzed. According to supper-modulus involute cylindrical gears used in rack and pinion jacking system of a windpower installation vessel. Finite element analysis model of rack and pinion was built; pinion profile shift x,pres-sure angle α,addendum coefficient haf*,modulem and width ofrack affect contact strength and bending strength of rack and pinion were studied with the FEA. The study resultsshow that every parameter has a large influence on the carrying capacity of rack and pinion,but their degrees of in-fluence are different.
2013, 32(2): 300-305.
Abstract:
According to the theory of dynamics,a scheme of computer simulation about the mechanical variablespeed explosive-proof mine hoister was established. The operation process of hoister was simulated by Simulink,and the influence of the speed regulation braking torque on the speed performance of hoister was analyzed. The sim-ulation results provide a theoretical reference for mine hoister.
According to the theory of dynamics,a scheme of computer simulation about the mechanical variablespeed explosive-proof mine hoister was established. The operation process of hoister was simulated by Simulink,and the influence of the speed regulation braking torque on the speed performance of hoister was analyzed. The sim-ulation results provide a theoretical reference for mine hoister.
2013, 32(2): 306-308.
Abstract:
A 3D continuum damage mechanics (CDM) model was applied for predicting the strength and damageevolution of notched composite laminates. Comparing the analytical results with the experimental data,the model inthis paper is capable of simulating the damage evolution of notched composite laminates from initial damage to finalcollapse,and has high accuracy and good calculation convergence. Based on this effective model,the damagepropagation of each layer under uniaxial tensile loading condition was analysed.
A 3D continuum damage mechanics (CDM) model was applied for predicting the strength and damageevolution of notched composite laminates. Comparing the analytical results with the experimental data,the model inthis paper is capable of simulating the damage evolution of notched composite laminates from initial damage to finalcollapse,and has high accuracy and good calculation convergence. Based on this effective model,the damagepropagation of each layer under uniaxial tensile loading condition was analysed.
2013, 32(2): 309-312.
Abstract:
For considering the characteristics of nonlinear time series and randomness,the phase space recon-struction method was put forward to study the chaos of a manufacturing system. Mutual information method andCAO's methods were used to determine the best delay time and the minimum number of embedding dimensions.The manufacturing system received phase space reconstruction under the time series of production efficiency.Then the number of correlation dimensions and maximum Lyapunov index were calculated by using Grassberger-Procaccia method and small data method. The calculation results show that chaos occur in the operation of a man-ufacturing system.
For considering the characteristics of nonlinear time series and randomness,the phase space recon-struction method was put forward to study the chaos of a manufacturing system. Mutual information method andCAO's methods were used to determine the best delay time and the minimum number of embedding dimensions.The manufacturing system received phase space reconstruction under the time series of production efficiency.Then the number of correlation dimensions and maximum Lyapunov index were calculated by using Grassberger-Procaccia method and small data method. The calculation results show that chaos occur in the operation of a man-ufacturing system.
