| dc.description.abstract | A study of the stress rupture time of glass fiber epoxy composite laminates in humid environments was investigated. Test specimens were made in order to compare the failure time of a saturated and non-saturated specimen in distilled water for a given constant force applied. Half of the samples made were placed in a 60 degrees celsius water bath and the weight gain was recorded to find when a fully saturated state was reached. Tensile testes were performed in order to validate the mechanical properties between specimens. Then a force was determined for each test below the ultimate tensile stress and held until failure. The time to failure for each test were then plotted on a graph. Two curve fit models on the form sigma_c = kt^m was produced from the scatter points. The curve for the saturated and non-saturated specimens were then compared to estimate the difference in behavior. The saturation process converged after 2700 hours at 60 degrees celsius. The tensile performance of the saturated specimens was reduced by 66% compared to the non-saturated specimens. The amount of data on the stress rupture plots were limited given by the time available. Therefore, a lot of uncertainties can be raised to the validity and repeatability of the findings. The two curves found from the stress rupture tests showed a correlation of the tensile performance between the saturated and non-saturated specimens. From the curve fitting it was seen that the tensile performance was 63% lower for the saturated specimens. However, the slop for the saturated specimens was steeper by 57%. Based on the the number of tests performed and the variance between each test, more tests are needed to support that a change of the slope is seen for similar tests. | |
