Engineering approach to static and fatigue behavior of flawed fiber-composite laminates
Simplified, engineering-analysis models are presented for predicting the response of notched and unnotched fiber composite laminates subjected to static and fatigue tensile loadings. The static failure model is an analytical idealization of the stress and damage distribution in a notched laminate. It avoids the study of extreme detail but models physically realistic failure modes. The failure predictions are compared with limited data for notched boron/epoxy laminates. A graded finite-element model is proposed to overcome certain limitations of the static-failure model. In the fatigue model, the responses of notched and unnotched laminates are predicted by using only limited experimental data for a unidirectional configuration or other simple laminate configurations. The model is based on a wearout concept wherein fatigue degrades strength and stiffness properties. This model is used to determine damage accumulation, lifetime, and residual strength for a notched laminate, and bounds on debond growth as a function of fatigue cycles for a debonded laminated beam. For nondestructive evaluation, these bounds enable the determination of the margins of safety for composite structural components after an elapsed time during service.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6213554
- Report Number(s):
- UCRL-81753; CONF-790307-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Fatigue of notched fiber composite laminates. Part 2: analytical and experimental evaluation
Composite materials - fatigue and fracture; Proceedings of the Symposium, Dallas, TX, October 24, 25, 1984