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Finite Element Simulation Of Single-Lap Shear Tests Utilizing The Cohesive Zone Approach, Wilson A. Perez
Finite Element Simulation Of Single-Lap Shear Tests Utilizing The Cohesive Zone Approach, Wilson A. Perez
Honors Undergraduate Theses
Many applications require adhesives with high strength to withstand the exhaustive loads encountered in regular operation. In aerospace applications, advanced adhesives are needed to bond metals, ceramics, and composites under shear loading. The lap shear test is the experiment of choice for evaluating shear strength capabilities of adhesives. Specifically during single-lap shear testing, two overlapping rectangular tabs bonded by a thin adhesive layer are subject to tension. Shear is imposed as a result. Debonding occurs when the shear strength of the adhesive is surpassed by the load applied by the testing mechanism. This research develops a finite element model (FEM) …
Nano-Particles In Multi-Scale Composites And Ballistic Applications, Jason Gibson
Nano-Particles In Multi-Scale Composites And Ballistic Applications, Jason Gibson
Electronic Theses and Dissertations
Carbon nanotubes, graphene and nano sized core shell rubber particles have all been extensively researched for their capability to improve mechanical properties of thermoset resins. However, there has been a lack of research on their evaluation for energy absorption in high velocity impact scenarios, and the fundamental mechanics of their failure mechanisms during highly dynamic stress transfer through the matrix. This fundamental research is essential for laying the foundation for improvement in ballistic performance in composite armor. In hard armor applications, energy absorption is largely accomplished through delamination between plies of the composite laminate. This energy absorption is accomplished through …
Low Strain Rate Studies Of Alumina Epoxy Composites Using Piezospectroscopy, Ashley Jones
Low Strain Rate Studies Of Alumina Epoxy Composites Using Piezospectroscopy, Ashley Jones
Electronic Theses and Dissertations
Particulate composites are widely used in many aerospace and military applications as energetic materials, armor materials or coatings and their behavior under dynamic loads have gained increasing significance. The addition of modifiers such as alumina nanoparticles generally facilitates the improvement of the mechanical strength to density ratio due to high specific area and particle rigidity. This allows for sufficient particlematrix bonding and therefore improved stiffness and load transfer in the composite. Photo-luminescent α-alumina nanoparticles when embedded in an epoxy matrix allow for the added benefit of in situ measurements at low strain rates to provide stress-sensitive information using the particle …
Failure Analysis Of Impact-Damaged Metallic Poles Repaired With Fiber Reinforced Polymer Composites, Robert Arthur Slade
Failure Analysis Of Impact-Damaged Metallic Poles Repaired With Fiber Reinforced Polymer Composites, Robert Arthur Slade
Electronic Theses and Dissertations
Metallic utility poles, light poles, and mast arms are intermittently damaged by vehicle collision. In many cases the vehicular impact does not cause immediate failure of the structure, but induces localized damage that may result in failure under extreme service loadings or can promote degradation and corrosion within the damaged region. Replacement of these poles is costly and often involves prolonged lane closures, service interruption, and temporary loss of functionality. Therefore, an in situ repair of these structures is required. This thesis examines the failure modes of damaged metallic poles reinforced with externally-bonded fiber reinforced polymer (FRP) composites. Several FRP …
On The Use Of Polyurethane Matrix Carbon Fiber Composites For Strengthening Concrete Structures, Zachary Haber
On The Use Of Polyurethane Matrix Carbon Fiber Composites For Strengthening Concrete Structures, Zachary Haber
Electronic Theses and Dissertations
Fiber-reinforced polymer (FRP) composite materials have effectively been used in numerous reinforced concrete civil infrastructure strengthening projects. Although a significant body of knowledge has been established for epoxy matrix carbon FRPs and epoxy adhesives, there is still a need to investigate other matrices and adhesive types. One such matrix/adhesive type yet to be heavily researched for infrastructure application is polyurethane. This thesis investigates use of polyurethane matrix carbon fiber composites for strengthening reinforced concrete civil infrastructure. Investigations on mirco- and macro-mechanical composite performance, strengthened member flexural performance, and bond durability under environmental conditioning will be presented. Results indicate that polyurethane …