Experimental Study on Stress Relaxation Behavior of Beryllium Bronze C17500
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摘要: 铍青铜C17500作为超导材料用于电力连接器的弹簧触指。为了预防弹簧触指的应力松弛现象,从铍青铜材料本身应力松弛特性入手研究,建立基于Norton蠕变理论的单轴应力松弛模型,并结合Arrhenius理论进行模型改进。通过不同载荷和不同温度下的铍青铜应力松弛试验,拟合出改进的应力松弛本构方程,得出不同载荷和不同温度下模型参数的预测曲线,依据预测曲线实现对铍青铜材料在特定温度下不同应力水平的应力松弛特性分析。Abstract: In order to prevent the stress relaxation of the spring contact fingers in power connector, a uniaxial stress relaxation model based on the Norton creep theory is established to prevent the stress relaxation behavior of beryllium bronze C17500. And a model improvement is carried out in combination with the Arrhenius theory. The modified stress relaxation constitutive equation is fitted through the stress relaxation test of the metal bronze under different loads and different temperatures. The predicted curves of the model parameters at different loads and different temperatures are obtained. The stress relaxation characteristic analysis on different stress levels at a specific temperature is realized according to the prediction curve.
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Key words:
- beryllium bronze C17500 /
- spring finger /
- creep /
- stress relaxation /
- Arrhenius theory /
- strength of materials /
- constitutive equation /
- test
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表 1 铍青铜C17500化学成分表
Cu Be Fe Mg Si 余量 0.25~0.4 0.1 0.02 0.2 表 2 铍青铜C17500物理性能和力学特性
密度/
(kg·m-3)弹性模
量/GPa热膨胀系
数/℃-1热传导系数/
(W·(mg℃)-1)屈服强
度/MPa延伸效
率/%8 830 138 1.76×10-6 208 951 14 表 3 恒温不同载荷下的松弛模型参数
试验载荷/
MPa松弛极限/
MPa材料参数 温度参数 应力指数 200 46.58 7.2×10-3 3 250.68 2.670 8 175 69.99 6.2×10-4 3 250.98 3.150 4 150 77.33 2.9×10-5 3 250.49 3.681 2 125 80.54 1.25×10-6 3 250.51 4.322 7 100 82.51 1.66×10-7 3 250.26 5.115 2 表 4 预测曲线拟合表达式
曲线 表达式 相关系数 y=1.711x-9.339 0.993 lnB0-lnσ0 y=18.47x-102.8 0.999 n-lnσ0 y=-3.415x+20.79 0.999 表 5 200 ℃、220 MPa下的松弛模型参数
松弛极限 材料参数 温度参数 应力指数 28.54 MPa 0.041 6 3 250.65 2.370 9 表 6 恒载200 MPa不同温度下的模型参数表
试验温度/
℃松弛极限/
MPa材料参数 温度参数 应力指数 200 46.5 7.2×10-3 3 250.67 2.670 8 175 66.95 1.18×10-4 2 549.64 2.670 8 150 80.15 2.21×10-5 1 729.36 2.670 8 125 89.33 5.49×10-7 1 083.71 2.670 8 100 120.1 3.34×10-8 581.604 2.670 8 表 7 恒载不同温度下的预测曲线拟合表达式
曲线 表达式 相关参数 y=-124x+0.331 5 0.963 y=-2 466x+7.061 0.997 y=6.058×105x-6 043 0.997 -
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