Y.Y.Yang
,
M.Mahfouf
,
D.A.Linkens
材料科学技术（英文）
The accuracy of numerical simulations and many other material design calculations, such as the rolling force, rolling torque, etc., depends on the description of stress-strain relationship of the deformed materials. One common method of describing the stress-strain relationship is using constitutive equations, with the unknown parameters fitted by experimental data obtained via plane strain compression (PSC). Due to the highly nonlinear behaviour of the constitutive equations and the noise included in the PSC data, determination of the model parameters is difficult. In this paper, genetic algorithms were exploited to optimise parameters for the constitutive equations based on the PSC data. The original PSC data were processed to generate the stress-strain data, and data pre-processing was carried out to remove the noise contained in the original PSC data. Several genetic optimisation schemes have been investigated, with different coding schemes and different genetic operators for selection, crossover and mutation. It was found that the real value coded genetic algorithms converged much faster and were more efficient for the parameter optimisation problem.
关键词:
Genetic algorithms
,
null
,
null
,
null
,
null
申发兰
,
陈明和
,
冯建超
宇航材料工艺
对TA15合金进行600～ 700℃下的应力松弛试验和675～800℃下的单向拉伸试验,研究其应力松弛行为的特征及影响因素,得出TA15合金在高温下的流变应力行为规律.结果表明,在600 ～ 700℃下TA15合金应力松弛行为可以分为两个阶段:第一阶段为应力松弛过程前100 s,试样内的残余应力快速下降；第二阶段残余应力下降缓慢,经过1 500s后剩余应力基本不变,趋向于某一个极限值；温度对应力松弛影响很大,温度越高,应力松弛越快；初应力、预应变、轧制方向对应力松弛影响不大,且随温度的升高影响变小.在675 ～800℃下TA15合金流变应力随温度的升高而降低,通过对单拉试验数据进行拟合,得出TA15合金流动应力符合第一类本构方程.
关键词:
TA15合金
,
应力松弛
,
流变应力
