Browsing by Subject "Glass -- Testing"
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Item Chemical structure origins of the normal force response in polymeric glasses(Texas Tech University, 2004-12) Flory, AnnySimultaneous normal force and torque measurements were made as a function of deformation and temperature in a series of polymeric glasses with different chemical structures. A large normal force with a fast relaxation rate was found in two n-alkyl methacrylates, PMMA and PEMA. Examination of the change in volume during torsion of PMMA samples cannot explain the large normal force response observed. When the measurements are expanded to polycarbonate and polysulfone, no difference is found between torque and normal force behaviors. The results show that the normal force response in PMMA and PEMA is influenced by their large sub-vitreous p relaxation which has been attributed to side chain motions. In this work the data are analyzed in the context of a time dependent modification of Rivlin's finite elasticity model which allows us to extract the first and second derivatives of the strain energy density function, W1 and W2. Very interestingly, polycarbonate and polysulfone exhibit a behavior closed to neo- Hookean (W2 = 0) while for PMMA and PEMA W2 decreases with time. The microstructural origins of these behaviors are thoroughly examined.Item Comparison of window glass sample strength estimates: full scale versus concentric rings(Texas Tech University, 1987-05) Hsu, Sheng-yungNot availableItem Experimental behavior of structurally glazed insulating glass units(Texas Tech University, 1989-05) Bailey, James RobertStructural glazing has become a popular method for finishing building exteriors in recent years. Structural glazing is a system of bonding glass, stone, or other materials to the structural frame of a building using structural silicones. Twenty-five to 40 percent of all new commercial glazing is structural glazing. More complex structural glazing systems use insulating glass (IG) units with structural silicone applied to all sides. No mechanical fasteners exist to hold the IG units in place. This design poses several interesting problems for engineers. Researchers at Texas Tech University conducted tests on eight structurally glazed IG unit samples. The National Science Foundation and several members of industry sponsored the research. These eight structurally glazed IG unit samples underwent applied simulated wind pressures on one or both sides. Instruments measured changes in structural seal and IG seal shapes. This dissertation defines changes in structural seal and IG seal shapes as the samples deform under pressure. This dissertation also discusses the behavior of these eight structurally glazed IG unit samples.Item Experimental study of glass plate strength at rapid loading rates(Texas Tech University, 1986-12) Pal, Himansu SekharThe time dependent nature of the strength of glass plates, commonly referred to as "static fatigue," is modeled by an equation involving an exponent "n" which is a material property relating to the rate of loading. Except for field explosion and shock tube tests, which were not instrumented for detailed response, glass plate tests to date have been essentially static. The highest loading rate achieved so far in a laboratory has been 3.6 psi/sec. The main objective of this study is to investigate the value of "n" at rapid loading rates. Secondary objectives are experimental verification of a nonlinear analytical model for dynamic plate response and of a dynamic failure prediction model for window glass. This dissertation presents and evaluates results of six series of tests to failure on 27" x 32" x 0.088" glass plates for loading rates ranging between 0.01 and 240 psi/sec. Each test series consisted of at least twenty specimens. The series with the slowest loading rate was tested in a conventional static test set-up. For the other five series, each plate was loaded in uniform air suction by rapidly pulling a plunger away from the plate which was mounted on a chamber. In the two series with slower loading rates, the plunger movement was controlled by a universal testing machine. For the three series with faster loading rates, the plunger was activated by a dropping weight. For the oscillating stress-time histories found at the most rapid loading rates, direct determination of "n" is not judged to be appropriate, and an indirect method is employed. The value of "n" is found to increase as the loading rate increases. The nonlinear dynamic finite difference model is shown to agree well with the experimental plate response, and the dynamic failure prediction model for glass plates is validated by the breakage results. The results of these experiments should aid in the prediction of the strength of window glass plates under rapid loading.Item Field instrumentation of glass plate response to low-level blast wave(Texas Tech University, 1988-05) Lo, Ah LoyNot availableItem The effect of the static fatigue constant upon window glass strength characterization(Texas Tech University, 1986-12) Hwang, Yuh-shingNot availableItem The experimental verification of the state of stress on a square glass plate loaded by concentric rings(Texas Tech University, 1986-12) Knox, John DennisNot availableItem The strength of new window glass using surface characteristics(Texas Tech University, 1984-08) Kanabolo, Diboro CelestineNot availableItem Weathered window glass strength evaluation using the ring-on-ring tester(Texas Tech University, 1986-12) McFarquhar, Dudley GeorgeNot available