CAJ | 학술논문

为了深入研究塑性强化材料在平行辊式矫直过程中一次反弯与二次反弯特性的关系，根据工程弹塑性力学的基本原理，建立基于强化弹塑性材料辊式矫直弯曲力学模型。通过解析法描述两次反弯过程中的应力关系，给出辊式矫直过程中截面弯曲过程材料残余应力分布、弯矩比、加载应力变化过程。证明两次反弯过程中经历一次反弯后，二次反弯截面弯矩比与曲率比不再是原有简单 M-C 关系，而是与一次弯曲曲率比、二次弯曲曲率比与强化系数相关的函数。理论上证明原有弯曲理论不再完全适用于多次连续反弯矫直过程。解析结果表明，辊式矫直过程中经历二次反弯的材料截面弹性极限弯矩值下降，矫直弯曲减小，回弹比增大。同种材料考虑强化与不考虑强化矫直后残余应力均方差分别为71.2与65.6，回弹比均值分别为0.49和0.43。
위료심입연구소성강화재료재평행곤식교직과정중일차반만여이차반만특성적관계，근거공정탄소성역학적기본원리，건립기우강화탄소성재료곤식교직만곡역학모형。통과해석법묘술량차반만과정중적응력관계，급출곤식교직과정중절면만곡과정재료잔여응력분포、만구비、가재응력변화과정。증명량차반만과정중경력일차반만후，이차반만절면만구비여곡솔비불재시원유간단 M-C 관계，이시여일차만곡곡솔비、이차만곡곡솔비여강화계수상관적함수。이론상증명원유만곡이론불재완전괄용우다차련속반만교직과정。해석결과표명，곤식교직과정중경력이차반만적재료절면탄성겁한만구치하강，교직만곡감소，회탄비증대。동충재료고필강화여불고필강화교직후잔여응력균방차분별위71.2여65.6，회탄비균치분별위0.49화0.43。
In order to further study the relevance between the first and the second reserve bending in the process of parallel roller level of plastic hardening material. Roller level bending mechanical model is established based on hardening elastic-plastic material in accordance with the fundamental of engineering elastic-plastic mechanics. The stress relevance of the two reserve bending processes is described by analytical method and discussed out the changing process of residual stress distribution, moment and loading stress with the section bending process of the roller level. With this model it is demonstrated that moment ratio and curvature ration is not simple “M-C” relation any longer, but function related to the first curvature ratio, the second curvature ratio and hardening factors. It is theoretically proved the original curvature theory can not apply to multi-reserve bending leveling processes. Analytical results show that during the second reserve bending process, there are decreased elastic limit bending moment and the bending moment in leveling process but increased spring-back ratio. Considered hardening of the same material residual stress mean square deviation are 71.2 and 65.6, average rebound ratio are 0.49 and 0.43.