A5070533171- Mechanical Behavior of Composites
- Fluid Dynamics Simulations and Interactions
- Fiber-reinforced polymer composites
- Numerical methods in engineering
- Wood Treatment and Properties
- Composite Material Mechanics
- Fatigue and fracture mechanics
- High-Velocity Impact and Material Behavior
- Natural Fiber Reinforced Composites
- Material Properties and Processing
- Spectroscopy and Quantum Chemical Studies
- Mechanical stress and fatigue analysis
- Composite Structure Analysis and Optimization
- Photosynthetic Processes and Mechanisms
- Hydraulic Fracturing and Reservoir Analysis
- Geotechnical Engineering and Underground Structures
- Smart Materials for Construction
- Metal Forming Simulation Techniques
- Molecular spectroscopy and chirality
- Polymer crystallization and properties
- Structural Behavior of Reinforced Concrete
- Fluid Dynamics and Heat Transfer
- Seismic Imaging and Inversion Techniques
- Masonry and Concrete Structural Analysis
- Surface Modification and Superhydrophobicity
Oregon State University
2015-2024
Corvallis Environmental Center
2013-2024
Google (United States)
2016
University of Utah
1997-2006
DuPont (United States)
1982-1987
Experimental Station
1982-1985
Lawrence Berkeley National Laboratory
1979-1983
University of California, Berkeley
1979-1983
Dartmouth College
1977-1981
Oak Ridge National Laboratory
1978-1979
A variational analysis approach has been used to determine the two- dimensional thermoelastic stress state in cross-ply laminates of type [0 m /90 n ] s and [90 / 0 . The was calculate energy release rate due formation a new microcrack. accurately includes effect residual thermal stresses. When compared with experiments, expressions are found predict typical data using single value for critical microcrack ing. This physical interpretation as microcracking fracture toughness or an...
A new algorithm is described which extends the material point method (MPM) to allow explicit cracks within model material. Conventional MPM enforces velocity and displacement continuity through its background grid. This approach incompatible with are discontinuities. By allowing multiple fields at special nodes near cracks, (called CRAMP) can cracks. The results provide an “exact” analysis for Comparison finite element experiments show it gets good crack problems. intersection of surfaces...
Design principles for nanostructures are proposed based on the controlled folding of strained thin bilayer films. By controlling geometry films, calculations can predict formation structures such as nanorings, nanodrills, and nanocoils (see Figure). In theory, this approach could be applied to fabrication from other combinations different classes materials.
Abstract We present a thermoelastic analysis of the composite cylinder model for undirectional including anisotropic fibers and an interphase region. have found magnitude residual thermal stresses on micromechanics level induced by differential shrinkage between matrix. For typical composites largest stress is tension along fiber direction, simple lower bound expression this given. Prediction requires knowledge physical properties The relevant epoxy thermoplastic matrices are discussed. can...
Fiber-reinforced polymer composites are being studied for many applications because of their potential outstanding mechanical properties. To be used in new applications, have to more fully understood. The fiber, the matrix, and fiber/matrix interface building blocks that need study. This research has concentrated on where debonds, or damage thoroughly. experimental work here focused fragmentation test. specimens were AS4-carbon/Epoxy E-glass/Epoxy composites. process was continuously...
Abstract Several stress analysis methods were used to find the energy release rate for initiation of an interfacial crack in a microbond specimen. First, we recently-derived variational mechanics stresses Previous studies growth have shear-lag methods. For second analysis, present new, and more complete, Third, consider some previously-published theories. each analyses, calculated was predict debonding as function droplet length. The predictions compared with two experimental results. Our...
Abstract We have extended the essential work of fracture technique to allow for determination plane‐strain fracture. The new is measure specific as a function ligament length in deeply double edge notched samples. This type data then experimentally corrected remove plastic and leave only length. By extrapolating zero‐ligament length, we claim be measuring was applied two rubber toughened nylons series polyethylenes. found independent thickness. Where comparison can made J ‐integral testing,...
Recently, a variational mechanics analysis approach has been used to de termine the thermoelastic stress state in cracked, cross-ply laminates (Nairn, J. A. 1989. Comp. Mat. , 23:1106). The included calculation of energy release rate due formation microcrack 90° plies. This paper describes series ex perimental results on wide variety composite material systems and layups generic type [0 m ,/90 n ] s . can be predict all features experimental draw some new conclusions about progression damage...
Using the shear-lag model, we have solved for crack-tip stress concentrations in double-edge notch and center unidirectional composites of finite width. From stress-state solution, expressions are derived strain energy release rate due to crack propagation through fibers parallel fibers. It is pro posed that these new equations, which include geometric correction factors, may be used fracture mechanics analyses their use will vide better physical insight into composite fracture. Because...
The problem of calculating the energy release rate for crack growth in an arbitrary composite presence residual stresses is considered. First, a general expression given arbitrary, mixed traction, and displacement boundary conditions. This result then applied to series specific problems including statistically homogeneous composites under traction or conditions, delamination double cantilever beam specimens, microcracking transverse plies laminates. In many examples, can be reduced finding...
This paper reformulates the axisymmetric form of material point method (MPM) using generalized interpolation (GIMP) methods. The reformulation led to a need for new shape functions and gradients specific axisymmetry that were not available before. differ most from planar near origin where r = 0. A second purpose this was evaluate consequences on variety MPM extensions have been developed since original work MPM. These included convected particle domain integration (CPDI), traction boundary...