Paper number 1365

ON A ROLE OF FIBRE-MATRIX INTERFACES IN THE CONTEXT OF NEAR-SURFACE STABILITY ANALYSIS OF COMPOSITE MATERIALS

Yuri N. Lapusta and Werner Wagner

Timoshenko Institute of Mechanics
Nesterov Sir. 3, Kiev, 252057 Ukraine
Institut fur Baustatik, Universitat Karlsruhe (TH)
Kaiserstrasse. 12, D 76731 Karlsruhe, Germany

Summary

Interfaces and interphases play an important role in reliable performance of composites and structures, since their defects can be a factor triggering numerous local failure mechanisms. This, in turn, contribute to a possible global failure of a structure element. The nature of the degradation process initiated this way depends greatly on the composite layout, mechanical properties of composite constituents, type and orientation of the components, the applied load etc. So many factors are often to be included into consideration, that researchers have to study a variety of cases individually and with considerable simplifications (application of 2D, iD models, homogenization etc.). However, to obtain sufficiently accurate and rigorous results, one should apply three-dimensional linearized equations to each constituent of a composite or structure. This report cuntains an attempt of developing an improved micromechanics-based 3D approach to near-surface stability analysis of composite materials in compression with special emphasis on possibility of incorporating specific fibre-matrix interface properties and classification of problems in dependence on the size of the damaged interface area.

Keywords

interface imperfections, near-surface stability analysis, upper and lowerbounds for critical loads.