On Design of Off-Axis Specimens
Abstract
The effort reported herein relates to (a) investigation of techniques to achieve uniformity of axial stress distribution in the test area between tabs on an off-axis specimen and (b) assessment of a fixed-angle off-axis specimen to perform as a shear specimen. On the basis of studies conducted, it is determined that off-axis specimen, subject to uniaxial loading, develop practically uniform axial stress provided (a) rotating end grips are used and (b) the fiber angle of cross-ply tab material and the inclination of tab ends are simultaneously optimized. This tab design retains its superior characteristics even in the nonlinear material range. The performance of off-axis specimens to function as shear specimens was assessed using both linear and nonlinear material behavior. Three failure criteria, namely, Norris Criterion, Tsai Criterion and Chamis Criterion were used in the linear analysis. In the case of nonlinear material behavior, a criterion based upon axial, transverse and shear energies of unidirectional laminates under simple load conditions was used. The results of studies, based upon linear and nonlinear material behavior, indicate that the off-axis angle required to generate the maximum shear response is not a fixed entity. It changes with changes of material and material behavior.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA154328
Entities
People
- George P. Sendeckyj
- Raghbir S. Sandhu
Organizations
- Wright Laboratory