Abstract
The contribution of structural effects to measured indentation data on composite plates and shells is explored to identify mechanisms/regimes where the resulting contact laws are significantly affected. Static indentation testing in composite materials is a critical experimental tool for understanding the overall impact response by providing contact laws for modeling purposes, and indentation itself has been used as a damage resistance metric. Structural effects on the indentation of a composite structure with a rigid indentor include the previously identified 'wrapping' effect, and a second effect identified here as through-thickness Poisson expansion/contraction. Both effects represent a global (or structural) contribution to a local measurement that is undesirable from the standpoint of modeling impact. Results from static indentation tests of convex shells (some undergoing buckling), concave shells, and plates are presented. Through-thickness Poisson contraction/expansion occurs in plate and shell structures due to membrane stresses that develop due to (in-plane) boundary conditions imposed on the composite test articles. A straightforward predictive scheme for the effect is developed utilizing classical laminated plate theory (CLPT) to calculate laminate through-thickness Poisson's ratios, and von-Karmann nonlinear plate equations to calculate the membrane stress driving the Poisson expansion/contraction. Composite plates are shown to have negligible indentation contribution from the Poisson effect for a wide range of structures within reasonable load, deflection, and damage regimes. A simple parametric study of plate impact indicates that accurate contact laws are only needed for thick plates. By contrast, experimental evidence for convex shells shows that contact laws are significantly affected by structural behavior, which is attributed to wrapping. copyright
Original language | English (US) |
---|---|
Pages (from-to) | 547-563 |
Number of pages | 17 |
Journal | Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference |
Volume | 1 |
DOIs | |
State | Published - 2005 |
Event | 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference - Austin, TX, United States Duration: Apr 18 2005 → Apr 21 2005 |
All Science Journal Classification (ASJC) codes
- Architecture
- General Materials Science
- Aerospace Engineering
- Mechanics of Materials
- Mechanical Engineering