Reduction of Free-Edge Stress Concentration
Abstract
The paper describes a quasi-three dimensional formulation and associated finite element model for the stress analysis of a symmetric laminate with free-edge reinforcement. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement. A proposed method of reducing the intensity of these large stresses is to reinforce the stiffness at the free edge by wrapping a lamina or collection of laminae around the free edge, forming a cap. The cap is intended to reduce the large displacement gradients near the free edge, thereby decreasing the interlaminar stresses and reducing the probability of delamination. Experimental studies indicate that a reinforcing cap is a viable method of maintaining laminate strength 15. The purpose of this study is to determine the effect of a reinforcing cap on the stress distribution in a symmetric composite laminate under uniform axial extension. Parametric studies are performed by varying the thickness, length, and lamination scheme of the cap. Numerical results are presented for several representative test cases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1985
- Accession Number
- ADA150732
Entities
People
- Junuthula N. Reddy
- P. R. Heyliger
Organizations
- Virginia Tech