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Buckling and Postbuckling Behaviors of Composite Panels with a Delamination

分层复合材料板的屈曲和屈曲后行为

基本信息

批准号：
63550061
负责人：
SUEMASU Hiroshi
金额：
$ 1.09万
依托单位：
SOPHIA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63550061/
关键词：
Composite Materials Panel Buckling Postbuckling Delamination Rayleigh-Ritz CAI Rayleigh Ritz 平板 Rayleigh-Ritz法

项目摘要

Interlaminar delaminations are introduced easily in the interlaminar area of composite panels by the impact loadings, fatigue etc owing to its weak interlaminar fracture toughness. The decrease of the bending rigidity due to the delaminations causes significant drops of the buckling load and the compressive strength of the panel. This problem is called CAI (Compression After Impact)". CAI is an urgent issue for the wider application of the composite materials to the airplane structures, because it often becomes critical for the design of the composite structures of airplanes. The objective of the present research is to get the data to improve the properties of the composite materials against CAI. The effects of delamination size and position on the buckling and postbuckling behaviors are studied analytically and experimentally about unidirectionally reinforced composite square panels in the first year and woven composite laminates in the second year. The square panels are clamped on the four sides and studied as a two dimensional panel in order to clarify the effects of the delamination on the more realistic structure. The complex mechanisms of the compressive property degradation owing to the delamination are observed and investigated. The analysis developed in the present research based on the Rayleigh-Ritz approximation can explain well not only the buckling behaviors but also the very complex postbuckling behaviors including secondary buckling.

由于复合材料层间断裂韧性较弱，在冲击载荷、疲劳载荷等作用下，容易在层间区域产生层间分层。由于分层引起的弯曲刚度的降低导致板的屈曲载荷和压缩强度的显著下降。这个问题被称为CAI（Compression After Impact）。计算机辅助设计是复合材料在飞机结构中广泛应用的一个迫切问题，因为它往往成为飞机复合材料结构设计的关键。本研究的目的是为改善复合材料的抗CAI性能提供数据。本文对单向增强复合材料方板和编织复合材料层合板分别进行了第一年和第二年的脱层尺寸和位置对屈曲和后屈曲行为的影响进行了理论分析和实验研究。四边夹紧的正方形面板，并作为一个二维面板研究，以澄清脱层对更现实的结构的影响。观察和研究了由于分层引起的压缩性能下降的复杂机制。基于Rayleigh-Ritz近似的分析方法不仅可以很好地解释屈曲行为，而且可以很好地解释包括二次屈曲在内的非常复杂的后屈曲行为。