Effect of stress concentrations in composite structures

Composite structures have found wide use in many engineering fields and a sound understanding of their response under load is important to their utilization. An experimental program is being carried out to gain a fundamental understanding of the failure mechanics of multilayered composite structures at GALCIT. As a part of this continuing study, the performance of laminated composite plates in the presence of a stress gradient and the failure of composite structures at points of thickness discontinuity is assessed. In particular, the questions of initiation of failure and its subsequent growth to complete failure of the structure are addressed

A Mechanical Model for Elastic Fiber Microbuckling

A two-dimensional mechanical model is presented to predict the compressive strength of unidirectional fiber composites using technical beam theory and classical elasticity. First, a single fiber resting on a matrix half-plane is considered. Next, a more elaborate analysis of a uniformly laminated, unidirectional fiber composite half-plane is presented. The model configuration incorporates a free edge which introduces a buckling mode that originates at the free edge and decays into the interior of the half-plane. It is demonstrated that for composites of low volume fraction (<0.3), this decay mode furnishes values of buckling strain that are below the values predicted by the Rosen (1965) model. At a higher volume fraction the buckling mode corresponds to a half wavelength that is in violation of the usual assumptions of beam theory. Causes for deviations of the model prediction from existing experimental results are discussed

Thermal Buckling of Metal Foam Sandwich Panels for Convective Thermal Protection Systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77175/1/AIAA-9741-678.pd

Macroscopic Finite Element for a Single Lap Joint

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76219/1/AIAA-2009-2449-244.pd

Non-localcontinuum modeling of carbon nanotubes;computation of spatial kernal using helical symmetry lattice dynamics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83587/1/AIAA-2010-2897-528.pd

The Influence of Cohesive Zone Modeling on the Stress Field and Energy Release Rates in a Cracked Elastic Body

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83572/1/AIAA-2010-2616-483.pd

Size Effects in the Crushing of Honeycomb Structures

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76537/1/AIAA-2004-1640-728.pd

Response of Actively Cooled Metal Foam Sandwich Panels Exposed to Thermal Loading

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76399/1/AIAA-24813-578.pd

Stress Gradient Effects on Notched Composite Failure Using a Local-Global Approach

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77170/1/AIAA-2004-1844-151.pd