Papers by Keyword: Debonding Damage

Abstract: Adhesive-bonded composite integrated structures (ACIS) are widely used in civil and military aircrafts now. The failure laws of such structures should be studied obligatorily to design them reasonably. In a composite wing-box test debonding damage was found at the connection between the skin and the wall in mechanical-joint region while the load was added up to certain magnitude. However the shear stress of the adhesive layer in plane was not high. The real reason of the damage is that there is significant out-plane normal tensile stress at the local place. The main factors, which induced out-of-plane normal tensile stress, include out-of-plane force resulting from changing of force transfer path and sudden change stiffness. In this paper an integrated composite I-beam is investigated to expound the existing objectively of out-of-plane force, and analyze the relationships between out-of-plane force, sudden change stiffness and out-plane normal tensile stress or peeling stress. Research indicates that the out-of-plane force and debonding damage resulted from it should be highly valued for ACIS in mechanical-joint region.

Abstract: This paper deals with an analysis of a crack-tip field of particulate-reinforced composites which can describe the evolution of debonding damage, matrix plasticity and particle size effect on deformation and damage. Numerical analyses were carried out on a crack-tip field in elastic-plastic matrix composites reinforced with elastic particles by using a finite element method developed based on an incremental damage theory. The particle size effect on damage is described by a critical energy criterion for particle-matrix interfacial debonding. The effect of debonding damage on a crack-tip field is discussed based on numerical results. The debonding damage initiates and progresses ahead of a crack-tip. The stress distribution shifts downward in the debonding damage area. It is concluded that a crack-tip field is strongly affected by debonding damage.