Damage in unidirectional graphite/epoxy laminates containing a circular hole

Conference · Tue Oct 01 04:00:00 EDT 1996

OSTI ID:385585

Yang, Fan; Chow, C L ^[1]; Fang, H Eliot ^[2]

---

1. Univ. of Michigan, Dearborn, MI (United States)
2. Sandia National Lab., Albuquerque, NM (United States)

In this paper, a damage mechanics model is described for determining progressive damage processes in unidirectional graphite/epoxy composite plates containing a central hole subjected to off-axis uniaxial tension. The inelastic behavior of these composite materials is attributed to the irreversible thermodynamics processes involving energy dissipation and stiffness variation caused by damage initiation and accumulation, The mechanical response of the composites is investigated by using a nonlinear finite element procedure formulated with a set of damage coupled constitutive equations. Separate damage criteria are derived for fiber failure and for matrix or fiber/matrix interaction failure in unidirectional composites. Validation of the damage model is achieved by comparing the numerical prediction and experimental data obtained from a Moire interferometry technique. It has been found that failure of the composite material near the hole region takes the form of an extensive damage zone. The macrocrack initiates at the material point near the hole boundary with a high damage value and propagates along the direction of damage zone extension. Preliminary results indicate that the proposed damage model is an effective method of studying progressive failure behavior of unidirectional composite laminates containing a circular hole and can be readily extended to examine the damage response of composite structures.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 385585
• Report Number(s): SAND--96-2323C; CONF-961105--12; ON: DE96015190
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS
COMPOSITE MATERIALS
CRACKS
EPOXIDES
FINITE ELEMENT METHOD
GRAPHITE
INTERFEROMETRY
MATHEMATICAL MODELS