摘要
缺陷敏感性是薄壁筒壳结构设计所面临的主要问题之一,通常利用折减因子来量化筒壳结构的缺陷敏感性程度.然而现有缺陷敏感性分析方法大多以预测筒壳折减因子下限为目的,未考虑不同形位公差水平对筒壳折减因子的影响.针对此问题,论文提出了一种考虑形位公差的薄壁筒壳折减因子预测方法.该方法基于多点最不利扰动载荷法进行最不利缺陷搜索,获得筒壳不同形位公差下的折减因子下限值,从而确定考虑形位公差的薄壁筒壳折减因子参考值,并利用不完全折减刚度法对计算过程进行加速.算例结果表明论文提出的筒壳折减因子预测方法可在保证安全可靠的前提下,有效提高折减因子预测精度,消除筒壳结构设计过程中不必要的安全裕度,对结构减重有积极意义.未来可基于该方法展开我国新一代航天结构薄壁筒壳折减因子设计规范的研究工作,进一步提高我国航天筒壳结构设计的精细化和轻量化水平.
Imperfection sensitivity is one of the main problems in the design of thin-walled cylindrical shell structures. The knockdown factor(KDF) is usually used to quantify the sensitivity to imperfections of the cylindrical shell structures. However, most of the existing imperfection sensitivity analysis methods aimed at predicting the lower bound of the KDF, and did not consider the influence of different geometric tolerance levels on the KDF of shells. Aiming at this problem, we propose a method to determine the KDF of thin-walled cylindrical shells considering geometric tolerances. Cylindricity is the most typical geometric tolerance index of cylindrical shells. Therefore, this study converts the geometric tolerance of cylindricity into the maximum allowable value of imperfection amplitude with further analysis. The procedure to determine the KDF of the thin-walled cylindrical shell with different geometric tolerances is based on the KDF lower bound of specific imperfection amplitude obtained by the worst perturbation load approach. The incomplete reduced stiffness method is used to accelerate the calculation process. An imperfection sensitivity analysis of a typical cylindrical shell with a diameter of 1 m is carried out to verify the accuracy and feasibility of the proposed method. The results of the examples show that the KDF determination method proposed in this paper can effectively improve the prediction accuracy of the KDF, and eliminate unnecessary safety margins under the premise of ensuring safety and reliability, which has a positive effect on the weight reduction for aerospace structures. This paper presents a versatile and simple numerical design method to update the overly conservative KDF design criteria for shell buckling. Based on this method, the research on the new KDF design criteria for thin-walled cylindrical shells of aerospace structures can be conducted, and the level of lightweight and detailed design for aerospace shell structures can be further improved.
作者
王博
王法垚
马祥涛
郝鹏
章凌
Bo Wang;Fayao Wang;Xiangtao Ma;Peng Hao;Ling Zhang(StateKey Laboratory of Structural Analysis for Industrial Equipment,Department of Engineering Mechanics,Dalian University of Technology,Dalian,116023;Beijing Institute of Astronautical Systems Enginering,Beijing,100076)
出处
《固体力学学报》
CAS
CSCD
北大核心
2022年第4期386-396,共11页
Chinese Journal of Solid Mechanics
基金
国家自然科学基金(11825202,11772078)
国防基础科研计划(JCKY2020110)
中央高校基本科研业务费(DUT20ZD104)
大连理工大学基本科研业务费(DUT2019TD37,DUT21GF201)
辽宁省自然科学基金(2019-YQ-01)
辽宁省创新人才计划(XLYC1907142,XLYC1802020)资助。
关键词
缺陷敏感性
形位公差
折减因子
不完全折减刚度法
多点最不利扰动载荷法
imperfection sensitivity
geometric tolerances
knockdown factor
incomplete reduced stiffness method
worst multiple perturbation load approach
