在煤矿生产中每年因圆环链失效造成的故障占了刮板输送机故障的一半以上。永久伸长变形是矿用刮板链主要失效形式之一，而刮板输送机运行过程中的超载是矿用圆环链永久伸长变形的重要原因之一。目前，对圆环链的永久伸长变形的研究大多侧重于链条残余塑性长度测量方法和测量工具等方面，对圆环链在不同负荷下残余应力应变、永久伸长变形量的研究相对较少。鉴于圆环链的永久伸长变形对降低因链条失效造成的故障具有重要的影响，本文对圆环链的永久伸长变形进行了分析研究，主要内容如下： (1) 利用弹塑性有限元软件ABAQUS计算模拟，分析了不同载荷对圆环链的永久伸长变形的影响，研究结果表明圆环链在超过正常工作负荷93%时圆环链的永久伸长量超过国家煤矿安全规定的更换链条标准； (2) 通过计算不同参数下(如屈服应力、切线模量、弹性模量、几何尺寸)圆环链的永久伸长变形，分析不同屈服应力、切线模量、弹性模量、几何尺寸下圆环链永久伸长变形的差异，可知几何尺寸和屈服应力对圆环链永久伸长变形的影响较大，切线模量与弹性模量对其影响较小； (3) 计算分析二次超载对圆环链的永久伸长变形量的影响，发现由于材料的屈服硬化二次超载比一次超载对圆环链的永久伸长变形量小。

The failure by round-link chain is more than half in the scraper conveyor failure in coal mine production. The permanent elongation deformation is one of the main failures in the scraper chain, and the overload of traction chains of scraper conveyor in active service would be induce the permanent elongation deformation of mining round-link chain. As so far, the permanent elongation deformation of round-link chain research mainly focused on the residual plastic length measurement methods of round-link chain and measurement tools and so on, while the analysis on the residual stress-strain and the permanent elongation deformation of round-link chain under different load is less. Because the permanent elongation deformation of round-link chain has important influence on reducing the failure caused by the round-link chain, the permanent elongation deformation of round-link chain is analyzed in this dissertation. Main research works performed are as follows: (1) By using elastic-plastic finite element software ABAQUS, the effect of the different loads on the permanent elongation deformation of the round-link chain is analyzed. The investigated results provide the permanent elongation deformation of the round-link chains will beyond the state coal mine safety regulation of the round-link chains replacement standard in more than 93% of the normal workload. (2) Through calculating the permanent elongation deformation of round-link chain under different parameters (such as yield stress and tangent modulus, elastic modulus and geometry size), the differences of the permanent elongation deformation of round-link chain under the different yield stress, tangent modulus, elastic modulus and geometry size is analyzed, it is concluded that the influence of geometry size and yield stress on the permanent elongation deformation of round-link chain is bigger, the influence of tangent modulus and elastic modulus on the permanent elongation deformation of round-link chain is smaller. (3) The round-link chain permanent elongation deformation of the secondary over-loading is calculated and analyzed, it is found that the effect of the secondary over-loading than the once over-loading on the permanent elongation deformation of round-link chain is small due to the strain-hardening of the material.