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Showing 1 to 20 of 63 for “"Microcracking"”.
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Fatigue Microcracking of Composite Material IM7/977-2
… based fracture mechanics approach to composite microcracking, experiments in fatigue were run on IM7/977-2 cross-ply laminates. Using a modified Paris Law approach, microcracking fatigue data is presented over a wide range of applied cyclic stresses. This Paris Law plot shows an "A" value of …
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Solvent induced microcracking in high performance polymeric composites
The first paper, “Dye Penetrant Induced Microcracking in High-Performance Thermoplastic Polyimide Composites”, studied the possibility of spurious microcracking in three high-performance thermoplastic polyimide composite materials due to zinc iodine dye penetrant. The material systems were …
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Microcracking in composite laminates under thermal and mechanical loading
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.
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Near Tip Mechanics of Stress Induced Microcracking in Brittle Materials
… ceramics) is sufficiently large, spontaneous microcracking can occur on cooling after processing. This damage can be avoided by controlling the grain or particle size.
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Transverse microcracking in Celion 6000 graphite/PMR-15 polyimide composite
… x-ray. The mechanical or thermal load at which microcracking initiates and the ply residual stresses were predicted using laminate analysis with stress and temperature-dependent materials. The TVM density as a function of tensile load was predicted using the multiple cracking theory proposed by …
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Investigation of Microcracking and Damage Propagation in Cross-Ply Composite Laminates
The present study investigates microcracking and damage progression in IM7/977-2, IM7/5555, and IM7/5276-1 [0/90/90/0] laminates. For each material system, seven to eight small coupons were axially loaded in a tensile substage. At increments of around 50 MPa the surfaces of the specimens were …
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Domain Switching and Microcracking in Ferroelectric Single Crystals and Polycrystalline Ceramics
In polycrystalline piezoelectric ceramics, electric field-induced cracking occurred by intergranular fracture. The macroscopic path of the crack growth depended strongly upon the applied field and the poling direction. Analysis showed that cracks extended along the place of maximum normal strain. …
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Microcracking Fracture Toughness for Graphite Epoxy Composite Laminates Using Finite Fracture Mechanics
… current study was undertaken to determine the microcracking fracture toughness in composite laminates using the energy release rate criteria. Three materials of specific interest in the aerospace industry – IM7/977-2, IM7/5555 and IM7/5276-1 – were analyzed. To evaluate the microcracking …
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Mechanical properties and microcracking behaviour of heterogeneous rocks after high-temperature treatment
… accurately predicting the mechanical properties, microcracking behavior, and strength evolution of heterogeneous rock under high-temperature conditions remains a key scientific challenge. This study investigates the mechanical behavior and microcrack evolution of heterogeneous rock, particularly …
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Investigation of Surface Displacements Induced in Loaded Cross-Ply Composite Laminates with Microcracking
… of a loaded composite laminate containing microcracking damage to explore the feasibility of using surface data to locate microcracks in laminates. In this study, finite element models are created for eleven different cross-ply IM7/977-2 laminates with ply numbers varying from four to ten. …
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Prediction of microcracking distributions in composite laminates using a Monte Carlo simulation method
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1997.
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The Effect of Long-Term Thermal Cycling on the Microcracking Behavior and Dimensional Stability of Composite Materials
The effect of thermal-cycling-induced microcracking in fiber-reinforced polymer matrix composites is studied. Specific attention is focused on microcrack density as a function of the number of thermal cycles, and the effect of microcracking on the dimensional stability of composite materials. …
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The effects of various levels of compressive stress fields on the deterioration rate and microcracking of plain concrete subjected to freezing and thawing
The results of this investigation indicate: 1. The deterioration rate in the lateral direction of the uniaxially prestressed members subjected to the deep-seated type of freeze-thaw damage increased as the level of the compressive stress field increased. 2. Under all levels of uniaxial compression, …
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Early Age Stresses and Creep-Shrinkage Interaction of Restrained Concrete
… for plain and fiber reinforced concrete (FRC). Microcracking forms a significant portion of drying creep of plain concrete, but it is less significant in FRC. Therefore, creep of FRC is dominated by real mechanisms, whereas apparent mechanisms induced by microcracking is significant in plain …
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An anisotropic damage model for rock
… is proposed for the constitutive description of microcracking processes in brittle rock under a general loading path. Experimental data and micromechanical models are reviewed to quantify the effect of microcracking on the material stiffness and the mechanisms of microcrack formation in brittle …
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Shear Fracture Growth in Granular Rocks and Porosity-Permeability Relationships in Mudstones
… pressures of 0-45 MPa. I employ the documented microcracking activity to calculate temporal trends of microcracking variance, fraction of shear microcracks to total microcracks, fractal dimension of microcrack locations, acoustic energy variance and seismic b-value. My results indicate that each …
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Fracture process zone : microstructure and nanomechanics in quasi-brittle materials
… microscopy investigations suggested increased microcracking near FPZ regions, and increased microcrack density with decreased grain size. Ultimately the study provides four contributions to the study of fracture of quasi-brittle materials: an algorithm for the automatic assessment of …
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Transformation induced plasticity in ceramics
… change in BaTi03. In addition, no evidence of microcracking was observed. The enhanced toughness in the vicinity of the transition temperature was attributed to limited plasticity at crack tips provided by the transformation shear strains. The effective strains at the crack tips required to …
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Investigation of Microcrack Growth in [0/90]s Graphite Epoxy Composite Laminates Using X-Ray Microtomography
… and this research concentrates on study of microcracking, delamination and other defects in the [0/90]s composite laminates of the above materials. These materials were uni-axially tested to pre-determined stress levels and the damages in the material were recorded in the form of microcrack …
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Oxidation behavior of laser clad nickel-aluminum-chromium-hafnium alloys
… hafnia-rich polycrystallites possibly via microcracking initiated by anisotropic thermall contraction of the hafnia. Laser cladding provides a large concentration of $\approx$1$\mu$m Hf-rich particles that are precursors of the hafnia in the scale as well as a fine dendrite spacing that …
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