铁素体球墨铸铁损伤力学特性的研究

Study on characteristics of damage mechanics of ferrite ductile iron

根据损伤力学的基本原理 ,利用测量电阻的方法 ,研究了拉伸受力状态下 ,铁素体球墨铸铁的损伤力学特性 .结果表明 ,当应力大于一定程度时 ,损伤发生 ,且随应力增加而逐渐增大 .并得出了损伤变量分别随应力和应变而变化的规律 .球墨铸铁存在着损伤阈值 ,其大小随球化率的提高而呈直线增大 ,但损伤阈值皆小于屈服强度 ,这一点对机械结构设计和选材具有重要参考意义 .临界损伤变量与球化率的关系不大 ,在本试验条件下 ,约为 0 0 6～ 0 0 68.

According to the principle of damage mechanics, the damage characteristics of ferrite nodular cast iron under uniaxial stress has been studied with the use of measuring electric resistance. The results showed that the damage in a nodular cast iron happened when the applied stress reached a certain extent, and the damage variable increased with stress. The evolutional law of damage variable as a function of stress was obtained. The damage threshold of nodular cast iron increased with nodularity, but it was lower than the yield strength, which is important to the design of mechanical stracture and the choice of materials. It was also found that the critical damage variable was not related to the nodularity, which is about 0 06～0 068.