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Fatigue Behavior Study Of Damaged Composite Laminates

Posted on:2010-10-01Degree:MasterType:Thesis
Country:ChinaCandidate:X L WangFull Text:PDF
GTID:2121360275976698Subject:Aircraft design
Abstract/Summary:PDF Full Text Request
With the rapid development of aeronautical technology, civil aircrafr design was amied at longer safe operating life. More and more composite structers were used in the airplane,which may endured severe fatigue loading.therefore, their fatigue behavior had great influences on the safety and realability of the aireplane. While damage torlance anylsis being an important part in structural integrity requirements and also a main principle in airplane design, the fatigue behavior study of damaged composite laminates had importance engineering significance.Started with the fatigue behavior analysis of T300/QY8911 unidirectional composite laminates, the q-lgN fatigue life curves were established according to experiment datas in the document. The damage function was deduced taking the fatigue modulus as intermediate variables and the transfermation of fatigue loads between different stress ratio through the apllication of the simplified constant life curve. After that,the quasi-three dimensional FEM model of multi-directional laminate was established in this paper .And the strength analysis and fatifue life prediction precedures were developed.Based on those precedures,the strength and fatigue life predictions of seven multi-directional composite laminates of different ply stacking sequence were performed, the results of which were compared with experient datas, verifying the rationality and validity. In the last part of this paper,in the study of fatigue behavior of damaged composite laminates,the laminates with a ply stacking sequence of [±45/0/90]4S and holes in different sizes,were analyed and their residual strength were calculated . Residual strength analysis of composite laminates with premade delamination in deffernt sizes and locations, whose ply stacking sequence was [45/-45/0/-45/0/45/90/45/-45/0/-45/0/45]s , were carried out afterwards. The results demonstrated the practical egineering application value of the analysis process for damaged composite laminares established in this paper.
Keywords/Search Tags:Composite Laminates, Fatifue, Damage Tolerance, FEM
PDF Full Text Request
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