Knockdown factor of buckling load for axially compressed cylindrical shells:state of the art and new perspectives  

轴压筒壳屈曲载荷折减因子评估方法的最新进展

作　　者：Bo Wang Peng Hao Xiangtao Ma Kuo Tian 王博;郝鹏;马祥涛;田阔(State Key Laboratory of Structural Analysis for Industrial Equipment,Key Laboratory of Digital Tiwin for Industrial Equipment,Liaoning Province,Department of Engineering Mechanics,Dalian University of Technology,Dalian 116023.China)

机构地区：[1]State Key Laboratory of Structural Analysis for Industrial Equipment,Key Laboratory of Digital Tiwin for Industrial Equipment,Liaoning Province,Department of Engineering Mechanics,Dalian University of Technology,Dalian 116023.China

出　　处：《Acta Mechanica Sinica》2022年第1期1-18,共18页力学学报（英文版）

基　　金：the National Natural Science Foundation of China(Grant Nos.U21A20429,11772078,and 11825202);the National Defense Basic Research Program(Grant No.JCKY2020110).

摘　　要：Thin-walled structures are commonly utilized in aerospace and aircraft structures,which are prone to buckling under axial compression and extremely sensitive to geometric imperfections.After decades of efforts,it still remains a challenging issue to accurately predict the lower-bound buckling load due to the impact of geometric imperfections.Up to now,the lower-bound curve in NASA SP-8007 is still widely used as the design criterion of aerospace thin-walled structures,and this series of knockdown factors(KDF)has been proven to be overly conservative with the significant promotion of the manufacturing process.In recent years,several new numerical and experimental methods for determining KDF have been established,which are systematically reviewed in this paper.The Worst Multiple Perturbation Load Approach(WMPLA)is one of the most representative methods to reduce the conservatism of traditional methods in a rational manner.Based on an extensive collection of test data from 1990 to 2020,a new lower-bound curve is approximated to produce a series of improved KDFs.It is evident that these new KDFs have an overall improvement of 0.1-0.3 compared with NASA SP-8007,and the KDF predicted by the WMPLA is very close to the front of the new curve.This may provide some insight into future design guidelines of axially compressed cylindrical shells,which is promising for the lightweight design of large-diameter aerospace structures.薄壁筒壳结构作为航空航天的主承力构件,在轴压载荷下易发生屈曲失稳,并且对几何缺陷表现为强敏感性.尽管经过数十年的研究,精准地预测几何缺陷影响下轴压简壳的折减因子仍是一个非常具有挑战的科学难题.直至现在,NASA20世纪提出航天薄壁轴压简壳折减因子下限设计准则SP-8007仍被广泛使用,随着制造工艺的进步和发展,SP-8007已经被证明过于保守.近年来,学者们基于数值方法和实验技术发展了一系列折减因子的确定方法,本文对这些方法进行了全面综述,其中作者提出的多点最不利扰动载荷法(WMPLA)是最具代表性的方法之一,其以合理的方式有效地降低了传统折减因子预测方法的保守程度.另外,本文还基于搜集的1990-2020年轴压简壳屈曲实验数据,对原始的折减因子下限准则曲线进行了改进.可以发现,相比于原始的SP-8007准则,新折减因子准则曲线整体上提升了0.1-0.3,并且使用WMPLA预测的折减因子非常接近于新准则曲线的边界.本文的研究工作有助于新-代轴压筒壳设计准则的建立,并可服务于大直径航天运载器主承力薄壁结构的轻量化设计.

关 键 词：Thin-walled structures Cylindrical shells Imperfection sensitivity Knockdown factor(KDF) Buckling experiment 

分 类 号：O35[理学—流体力学]