CAJ | 학술논문

考虑晶粒长大的超塑性本构模型能否成功模拟成形过程依赖于参数选取的好坏,由于该模型涉及多个物理过程且每个过程都很难同其他过程区别开来,同时模型中包含多个材料参数,因此很难通过试验直接识别模型中的材料参数.模型中材料参数通过反分析方法进行.给出需要识别参数的超塑性本构模型,以使晶粒尺寸-时间关系和应力-应变关系计算值和试验值差值的加权平方和最小化为目标,构造目标函数;基于参数物理意义和数值结果给出参数取值范围.基于目标函数特性构造-全局优化算法,该算法吸收遗传算法能进行全局搜索的优点和Levenberg-Marquardt算法和增广Gauss-Newton算法收敛速度比较快的优点.针对某些参数取值范围比较大的特点,设计出同时使用指数编码和传统实型编码的混合编码的遗传算子.最后以Ti-6Al-4V为例,应用构造的算法识别超塑性本构模型中的材料参数,计算结果和试验结果符合较好.
고필정립장대적초소성본구모형능부성공모의성형과정의뢰우삼수선취적호배,유우해모형섭급다개물리과정차매개과정도흔난동기타과정구별개래,동시모형중포함다개재료삼수,인차흔난통과시험직접식별모형중적재료삼수.모형중재료삼수통과반분석방법진행.급출수요식별삼수적초소성본구모형,이사정립척촌-시간관계화응력-응변관계계산치화시험치차치적가권평방화최소화위목표,구조목표함수;기우삼수물리의의화수치결과급출삼수취치범위.기우목표함수특성구조-전국우화산법,해산법흡수유전산법능진행전국수색적우점화Levenberg-Marquardt산법화증엄Gauss-Newton산법수렴속도비교쾌적우점.침대모사삼수취치범위비교대적특점,설계출동시사용지수편마화전통실형편마적혼합편마적유전산자.최후이Ti-6Al-4V위례,응용구조적산법식별초소성본구모형중적재료삼수,계산결과화시험결과부합교호.
Whether the superplastic constitutive model considering grain growth can successfully simulate the tbrtmng process depends on the quality of parameter identification.However,it is difficult to obtain satisfactory parameters by experiment directlY.The reasons are due to that it considers many physical processes and it is difficult to differentiate one physical process from other physical processes,at the same time,the model is involved many parameters.The material parameters are identified by the inverse analysis.The superplastic model is given;and the objective function is designed through minimizing the weighted square sum of the difference between the calculated value and the experimental value for the stress-strain relation and grain size-time relation;the zone of the parameter value is given based on the physical significance and the numerical result.A global optimiz ation method is developed on the basis of the characteristies of the objective function.The developed optimization method incorporates the advantages of making global search for the genetic algorithm;at the same time,the method incorporates the strengths of relatively fast convergent speed for the Levenberg-Marquardt algorithm and the augmented Gauss-Newton method. To the question of the relatively large zone of the parameter value,the hybrid coding genetic operators,which make use of the real coding and exponential coding simultaneously,are designed.At last,taking Ti-6Al-4V as an example,a set of satisfactory material parameters are obtained by using the developed method.The calculated results agree with the experimental results relatively well.