Thermoviscoelastic characterization and predictions of Kevlar/epoxy composite laminates

Thesis/Dissertation · Thu Dec 31 23:00:00 EST 1987

OSTI ID:5657586

Gramoll, K C

This study consisted of two main parts, the thermoviscoelastic characterization of Kevlar 49/Fiberite 7714A epoxy composite lamina and the development of a numerical procedure to predict the viscoelastic response of any general laminate constructed from the same material. The four orthotropic material properties, S{sub 11}, S{sub 12}, S{sub 22}, and S{sub 66}, were characterized by 20-minute static creep tests on unidirectional ((0){sub s}, (10){sub s}, and (90){sub 16}) lamina specimens. A new numerical procedure to predict long-term laminate properties from lamina properties (obtained experimentally) was developed. Numerical instabilities and time constraints associated with viscoelastic numerical techniques were discussed and solved. The numerical procedure was incorporated into a user-friendly microcomputer program called Viscoelastic Composite Analysis Program (VCAP), which is available for IBM PC type computers. The program was designed for ease of use and includes graphics, menus, help messages, etc. The final phase of the study involved testing actual laminates constructed from the characterized material, Kevlar/epoxy, at various temperature and load levels for 4 to 5 weeks.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA)
• OSTI ID: 5657586
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ARAMIDS
COMPOSITE MATERIALS
COMPUTER CODES
ELASTICITY
EPOXIDES
INSTABILITY
MATERIALS
MECHANICAL PROPERTIES
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
SYNTHETIC MATERIALS
TENSILE PROPERTIES
THERMOELASTICITY