摘要利用力尔 LCJ 材料力学教学试验机和力尔试验系统，设计四种不同的加载 速率以及两种不同的加载路径，通过对原始力学性能相同的同种低碳钢材料进行 的多次试验，研究不同加载速率和不同加载路径对低碳钢力学性能的影响，得到 不同加载速率和不同加载路径下的载荷-位移曲线、应力-应变曲线。此外，通过 上述低碳钢的拉伸试验，比较了同种低碳钢试件在不同加载速率及不同加载路径 作用下的弹性模量 E、屈服极限s 、强度极限b 、延伸率、断面收缩率、 试件断口的形状特征等。利用 ANSYS 软件进行低碳钢拉伸的数值模拟、并与试 验结果进行对比。最终结果表明：（1）在弹性阶段范围内，不同加载速率和不同 加载路径对低碳钢的弹性模量 E 影响不大；（2）在不同加载速率和不同加载路 径下，低碳钢的屈服强度s 基本保持稳定；（3）低碳钢的强度极限b 随着加载 速率的增大呈现出逐渐下降的趋势，而加载路径对低碳钢的强度极限b 基本没 有影响；（4）不同加载速率对低碳钢的延伸率、断面收缩率影响不大，而拉 伸过程中的加载-卸载-再加载的加载路径会使低碳钢出现冷作硬化现象（即试件 的弹性极限会提高，伸长率相应的减小）；（5）利用 ANSYS 软件数值模拟的结 果与实际测得的结果基本吻合。

该论文有图 69 幅，表 10 个，参考文献 36 篇。72683

毕业论文关键词：加载速率 加载路径 材料力学性能 拉伸试验 数值模拟

Experimental study on the effect of loading rate and loading path on the tensile properties of low carbon steel

Abstract Use of lifein LCJ material mechanics teaching test machine and lifein test system, designed four different loading rates and two different loading paths。 Through many experiments about the basic mechanical properties of the same species of low carbon steel materials, we can research that the effect on the mechanical properties of low carbon steel in different loading rates and different loading path conditions 。 at the moment, we can get the load-displacement curve and the stress-strain curve under the condition of different loading rates and different loading paths。 In addition, through the tensile test of low carbon steel, compared the elastic modulus, yield strength, ultimate strength, elongation, section shrinkage rate, shape characteristics of fracture and so on of the same low carbon steel specimens under  the  action  of different loading rates and different loading paths 。 The software of ANSYS was used for the numerical simulation of the tensile test of the low carbon steel, and the results of the numerical simulation were compared with the test results。 Finally, the results showed that: (1) within the range of the elastic, the elastic modulus E of low carbon steel had very little effection under different loading rates and  different  loading paths  ; (2) under the action of different loading rates and different loading paths, the  yield strength of low carbon steel remained stable; (3) with the increasing of the  loading rate, the strength limit of the low carbon steel showed a decreasing trend gradually, and there is no effect of the loading path toward the ultimate strength of the  low carbon steel; (4) the different loading rate has little effect on  extension ratio and section shrinkage rate of the low carbon steel, however, during the process of tensile test , the form of loading path within loading-unloading-loading angin ,the low carbon steel  appeared  the  cold  hardening  phenomenon  (i。e。  the  elastic  limit  of  the   test