摘要
有机玻璃[聚甲基丙烯酸甲酯(PMMA)]因其优异的性能在许多领域都得到广泛应用,以其为原材料的开孔构件会因孔边应力集中而导致结构的强度降低甚至失效。目前对于无限大板下圆孔应力集中的理论分析已经成熟,但对于有限宽板,由于自由边界和有限区域的存在,仍难以对圆孔孔边的应力分布进行精确计算。为了探究带孔PMMA有限宽板的孔边应力集中规律,针对PMMA材料,通过数字图像相关(DIC)对有限宽板下不同直径的圆孔孔边应力集中分布规律进行研究,实验结果表明:在固定板宽的情况下,随着孔径的增加,孔边最大应力集中系数提高,但圆孔远端应力低于板件所受平均应力,从而出现孔边应力趋于线性分布的现象。结合应力流原理对该现象进行了分析,并基于实验数据对有限宽板修正解进行验证,确定了有限宽板修正解的适用范围为:孔径/板宽之比Q≤0.3。考虑到离面位移对2D-DIC测量小变形的应变带来的误差,结合孔边区域应变电测法与2D-DIC对比试验结果,提出了一种依据离面影响因数来确定取值范围的方法,从而获得准确的应变数据。
Polymethylmethacrylate(PMMA)is widely used in many fields due to its excellent properties,and the open-hole components using it as the material can lead to the strength reduction or even failure of the structure due to the stress concentration at the hole edge.The theoretical stress concentration analysis in circular holes under the infinite plate was well established.However,for the finite-width plate,it is still difficult to accurately calculate the stress distribution at the hole edges of circular holes due to the existence of free boundaries and finite regions.To investigate the stress concentration law at the hole edge of PMMA finite-width plate with holes,the stress concentration distribution law at the hole edge of circular holes with different diameters under the finite-width plate by digital image correlation(DIC)for PMMA material was explored.The experimental results indicate that in a fixed width of the plate,with the increase of the diameter of the holes,the maximum stress concentration factor of the hole edge is increased,but the stress at the distal end of the holes is lower than the average stress applied of the plate,thus the phenomenon of linear distribution of the hole edge stresses appears.This phenomenon was analysed using the principle of stress flow,and based on the experimental data to validate the finite-width plate revised solution,it was determined that the applicable range of the finite-width plate revised solution is:ratio of diameter/plate-width Q≤0.3.Considering the error brought by off-surface displacement to the strain of small deformation measured by 2D-DIC,combining the results of the comparison test between the strain gauge and 2D-DIC in the area of the hole edge,a method to determine the range of values based on the off-surface influence factor was proposed,to obtain the accurate strain data.
作者
刘雯雯
王得志
段琨煜
王志
LIU Wenwen;WANG Dezhi;DUAN Kunyu;WANG Zhi(School of Mechanics and Safety Engineering,Zhengzhou 450001,China)
出处
《工程塑料应用》
北大核心
2025年第5期77-84,101,共9页
Engineering Plastics Application
基金
国家自然科学基金项目(52303047,52178257)。
关键词
数字图像相关
聚甲基丙烯酸甲酯
应力集中
圆孔
有限宽板
digital image correlation
polymethyl methacrylate
stress concentration
circular hole
finite-width plate
