Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 58 for “"Material Failure"”.
-
A Computerized Implementation of the Material Failure Logic Model Technique (Cad, Cae, Expert System, Optimization)
Everyone agrees that the fulfillment of a human need or desire is the first objective for any engineering design project. But, keeping the product working for the prescribed design lifetime is as important as producing a functional object. In other words, it is the primary responsibility of …
-
A Critical Evaluation of Computational Fracture Using a Smeared Crack Approach in MPM
… of the smeared crack representation of material failure using the material-point method (MPM) as a feasible computational failure approach is performed. The spatial descretization in MPM is defined by a grid of cells that represent space and a set of points that represent the deformable …
-
Effect of plastic strain on the corrosion of X65 pipeline steel
Corrosion is an important mode of degradation and failure for iron alloys used in oil and gas pipelines. Pitting corrosion is a particular type of corrosion that is not well-understood and can play in important role in material failure. Research has shown that areas of increased plastic strain …
-
Scuffing Under Starved Lubrication Conditions
… of macroscopic adhesions leading to bulk material failure due to plastic shearing.
-
Use of Material Tailoring to Improve Axial Load Capacity of Elliptical Composite Cylinders
… Post-buckling collapse behavior and material failure characteristics are also of interest. Two approaches to implementing a circumferential variation of lamination are examined. For the first approach the lamination sequence is varied in a stepwise fashion around the circumference. …
-
Machine Learning for Materials Science
… In this thesis, the use of machine learning in materials science is explored, for two different problems: the optimisation of gallium nitride optoelectronic devices, and the prediction of material failure in the setting of laboratory earthquakes. Light emitting diodes based on III-nitrides …
-
Prebuckling, Buckling, and Postbuckling Response of Segmented Circular Composite Cylinders
… the difference could be due to the fact material failure not included in the model plays a role in the cylinder response. For the circumferentially-stiff cylinder, the difference is definitely due to material failure characteristics not included in the model. The predicted postbuckling …
-
On the Effective Stiffness of Slender Concrete Masonry Walls
… A discrepancy between the expected and observed failure modes of slender walls loaded at low axial load eccentricities is noted in the analysis, whereby slender masonry walls commonly experience compressive material failure when loaded at a low axial load eccentricity, even though slenderness …
-
Failure Initiation and Progression in Internally Pressurized Non-Circular Composite Cylinders
In this study, a progressive failure analysis is used to investigate leakage in internally pressurized non-circular composite cylinders. This type of approach accounts for the localized loss of stiffness when material failure occurs at some location in a structure by degrading the local material …
-
Torsion of Elliptical Composite Cylindrical Shells
… and postbuckling responses are examined, and material failure is considered. Four elliptical cross sections, defined by their aspect ratio, the ratio of minor to major radii, are considered: 1.00 (circular), 0.85, 0.70, and 0.55. Two overall cylinder sizes are studied; a small size with a …
-
A Model for Prediction of Fracture Initiation in Finite Element Analysis of Bolted Steel Connections
… steel connections using damage mechanics. A material failure envelope has previously been developed for aluminum extrusions using the IDS (instability, ductile, and shear) criterion. The IDS criterion is a damage mechanics based model for defining failure envelopes. These failure envelopes …
-
Structural analysis of geodesically stiffened composite panels with variable stiffener distribution
… on buckling of the panel assembly and material strength failure. Material failure in the skin and stiffeners are estimated using a maximum strain criterion. The design variables that can be used for optimization include thickness of the skin laminate, stiffener thickness and height, and …
-
Optimal design of geodesically stiffened composite cylindrical shells
… as design variables. Buckling, displacement, and material failure constraints can be imposed on the design. The system is used to conduct a design study of geodesically stiffened shells. For comparison purposes, optimal designs of unstiffened shells and shells stiffened by rings and stringers are …
-
Fire Response of Loaded Composite Structures - Experiments and Modeling
In this work, the thermo-mechanical response and failure of loaded, fire-exposed composite structures was studied. Unique experimental equipment and procedures were developed and experiments were performed to assess the effects of mechanical loading and fire exposure on the service life of …
-
Ultimate Compression After Impact Load Prediction in Graphite/Epoxy Coupons Using Neural Network and Multivariate Statistical Analyses
… equation that predicts the ultimate failure load of an impacted damaged coupon based uniquely on the acoustic emissions it emits at low proof loads. Acoustic emission (AE) data were collected using two 150 kHz resonant transducers which detected and recorded the AE activity given off …
-
Quantifying the Constraint Effect of Three-Dimensional Specimens with Biaxial Loading Using the J-A2 Method
<p>Fracture toughness is an important material property used to assess the structural integrity of mechanical components containing cracks. Often, the fracture toughness depends upon the geometry of the component as well as the configuration and level of the applied loading. This dependence is …
-
An investigation into the behaviour of various sized fibre reinforced plastic beams
… conducted and discussed. The influence of the material quality (voidage) of bi-directional stitched glass fibre reinforced composite beam on beam performance was studied. It became apparent from the tests, that the void content plays a significant part in the strength and the mechanisms leading …
-
Modelagem de fratura dúctil em colisão de embarcações utilizando modelo de dano de Lemaitre modificado
… methodologies, and to simulate numerically the material’s ductile fracture, several failure criteria have been applied. With this perspective, thi3s article considers a new approach for the application of numerical analysis to ship collision and stranding, based on the Continuum Damage Mechanics …
-
The compressive failure of graphite/epoxy plates with circular holes
… were chosen to differentiate between stability failures due to buckling and strength failures due to the presence of the cutout. The critical load of the 24 ply panels was found to be independent of hole size with bifurcation occurring in the two halfwave mode longitudinally and one halfwave …
-
Viscoelastic Fluid Modeling for Geophysical Applications in an Eulerian Framework
… to a Maxwell viscoelastic constitutive relation. Material objectivity is enforced through the Jaumann (Corotational) time derivative, whose numerical behavior is examined and compared with related formulations from classical viscoelastic fluid modeling. Material failure is incorporated into the …
Page 1 of 3