Progressive Failure Analysis of Composites

Abstract

Recent developments in the aircraft industry towards substantially improving fuel economy and extending flight range have accelerated interest in the use of advanced composites as primary structural materials. The airframes of next-generation airliners will have substantial parts made of light-weight composites. This means that the engineering demands on the performance of fiber-reinforced composites will become greater. There is therefore a need to better understand and predict the multiple complex failure mechanisms in composite structures, and to devise more reliable failure theories and damage progression models. There is a large body of literature on progressive damage analysis in composites, much of which employs damage mechanics and material stiffness degradation methods. This article reviews some of the more recent work in this area and describes the issues pertinent to application in composite structures. The authors' ongoing research efforts in modeling and prediction of progressive damage through the relatively novel element-failure method (EFM), which has been coded into a user-defined UEL code in Abaqus, are discussed. In particular, results for notched composite laminates and pin-loaded (PL) analyses are shown and compared to experimental data. Although EFM is the computational platform on which the damage is advanced in the structure, the results are dependent on the choice of the failure criterion. Various failure criteria are used throughout the cases discussed herein, from the more traditional Tsai—Wu (TW) criterion to the very recently proposed micromechanics-based failure (MMF) criterion. The EFM may also be used with cohesive elements, with the former intended for modeling in-plane damage progression, while the latter for delamination onset and propagation. This hybrid EFM-cohesive element approach is illustrated with an analysis of double-notched composite laminate. The computational models are relatively robust up to and including ultimate load, and enable the mapping of extensive damage patterns in composite structures. They represent a suite of computational tools that extend the capability to model damage and failure propagation beyond initial failure prediction.

Development of Progressive Failure Analysis Method for Composite Laminates based on Puck's Failure Criterion-Damage Mechanics Coupling Theories

“…Chang and Chang (1987) Tay 등은 점진적 파손진전 현상의 효과적인 유한요소 구현을 위해 요소파손법(element failure method)을 제시하였다 (Tay, et al, 2008 (Hashin, 1980), Puck and Schürmann (1998; 에 의해 더욱 구체적으로 체계화되었다. Puck and Schürmann (1998; (1) 인장 상태에서의 섬유 파손(fiber failure in tension)…”

Study of the mechanical behavior of cortical bone microstructure by the finite element method

“…These theories have important differences with respect to less recent criteria as Tsai-Wu, because incorporate micromechanical aspects and differentiate between fiber or matrix dominated modes of failure (Tay et al [2008]). Both MCT and MMF evaluate the composite failure based on constituent stresses (fiber and matrix), but are based on different methods to calculate stresses.…”

“…As an alternative, the failure propagation after initiation has also been simulated through a progressive damage approach. This approach is based on a nonlinear FE analysis in which the stiffness properties are reduced at the element level as its stress state reaches a failure condition (Tay et al [2008]). This approach has been successfully applied in structural composite materials, such as fiber reinforced laminates (Tay et al [2008]; Chang and Chang [1987]; Hou et al [2000]; Lapczyk and Hurtado [2007]).…”

“…The simplest approach to carry out the reduction of the elastic properties is the direct material property degradation MPD (Tay et al [2008]; Chang and Chang [1987]; Hou et al [2000]). This method will be used in this work and consists in reducing the elastic properties by a fixed factor that can depend on the mode failure.…”

“…It is customary to assume that the stiffness in certain directions is reduced to 0 (Chang and Chang [1987]; Hou et al [2000]), although the analysis can lead to excessively conservative results and numerical difficulties. Tay et al suggest that a constant reduction factor of 0.1 is common practice in the literature due to its simplicity and convergence advantages (Tay et al [2008]). Other approaches are based on continuum damage mechanics (CDM), with a less arbitrary formulation, often based on thermodynamic principles.…”