基于内聚力模型的斜接修补复合材料强度分析

STRENGTH ANALYSIS OF SCARF-REPAIRED COMPOSITE MATERIAL BASED ON COHESION MODEL

在战争环境下,机身复合材料损坏会降低战机战斗力,如何通过修补恢复战机的作战能力是一个急需解决的问题。为探究修补复合材料的强度恢复规律,本文基于内聚力模型和有限单元法,建立斜接修补复合材料强度预测模型,并对缺陷尺寸、修复斜度等因素对强度的影响进行分析。结果表明:在0°与90°铺层的交点处出现应力集中现象,可达平均应力的6.3倍之多,该应力集中效应可能是斜接修复复合材料损伤的始发诱因。随着缺陷尺寸的增加,修复强度呈降低趋势。修补复合材料初期损伤主要萌生于胶层内部,当损伤尺寸大于3 mm后,损伤路径沿着界面发展。随着修补斜度的增加,强度呈增加趋势。从修补效率来看,斜度大于1∶15即满足修补要求。研究成果可为提升飞机复合材料修复工艺及修复效率评估提供理论依据。

In a war environment,the damage of fuselage composite material would reduce its combat effectiveness.Therefore,restoring combat capability through repair is an urgent problem to be solved.In order to explore the law of strength recovery of repaired composite materials,the strength prediction model of scarf-repaired composite material was established based on cohesion model and finite element method,and the influence of defect size and repair slope on strength was analyzed.The results indicate that,the stress concentration occurs at the intersection of 0°and 90°layers,and the stress can reach 6.3 times the average stress.The stress concentration effect may be the initial cause of the damage of the scarf-repaired composite materials.With the increase of defect size,the repair strength decreases.The initial damage of the scarf-repaired composite material is mainly generated in the adhesive layer,then the damage develops along the interface when the defect size is larger than 3 mm.With the increase of repair slope,the strength shows an increasing trend.In terms of repair efficiency,the repair slope greater than 1∶15 meets the repair requirements.The research results provide a theoretical basis for the repair technique and efficiency evaluation of aircraft composite materials.