A series of tensile, compression and shear tests in room temperature were carried out on carbon fiber reinforced polymer matrix composite materials (IM7/PEEKEK) to evaluate their mechanical properties. Also tensile tests at 160 degrees Fahrenheit (72 degrees Celsius) in longitudinal and transverse directions were done to study the effects of such temperature on the tensile strength of the mentioned composite materials. The setup of the testing equipment and the furnace that was used to provide elevated temperature conditions limited the possibility of conducting compressive and shear tests at high temperature as well as raising the temperature to higher levels. The experiments were set up in accordance with ASTM standards that best corresponded to the test specifications. Specimens were categorized into groups according to their nature of testing. All the specimens were reinforced at both ends by means of tabs which were bonded on both faces to reduce the effects of the external pressure exerted on them through the grips of the testing machines and were tested until failure. Load, elongation (displacement) and strain data were recorded by means of strain gages and data acquisition systems. The accuracy of the experimental data for the room temperature portion of the experiments is verified by comparing them to those of the most equivalent composite family, as having not been given any information regarding the structural properties and manufacturing processes of the composite materials that were used throughout the experiments made it difficult to find exact ASTM standards and reference materials for the testing and comparison of results. The results of the experiments showed that the tensile strength of this particular composite material is not effected by the 160 degrees Fahrenheit temperature; a point that is proved by the literature indicating their specific and sensitive application in aircraft heat dissipation [1].

Pressurized thick-walled cylinders undergo repeated cycles of high stress and temperatures that may severely shorten the life of the component. Testing pressurized cylinder can help to evaluate the strength of the cylinder. This research seeks to determine the pressure to which the component is subjected by instrumenting the outside of the cylinder, and to evaluate hoop strain and hoop stress of the internal and external surface of the pressurized thick-walled cylinder. This study provides experimental results and then compares them with theoretical and numerical data for the cylinder under investigation. Using the experimental method, an axial load up to 15,000 lb is applied to the cylinder using a Landmark 370 MTS unit to generate pressure inside the cylinder wall. Lame´ equations are used to calculate hoop stress theoretically. The numerical data is obtained using finite element simulation (ANSYS) to calculate hoop stress and hoop strain at the internal and external surfaces of the cylinder. This work provides useful information for evaluating the strength of thick-walled cylindrical structures in a laboratory setting.

A series of tensile, compression and shear tests were carried out on carbon-epoxy composite materials to evaluate their mechanical properties. The experiments were set upin accordance with ASTM standards that best corresponded to the test specifications. Specimens were categorized into groups according to their dimensions and shape. Based on testing requirements, some were cut into rectangular and others into dog bone specimens to determine the effects of stress concentration. A number of specimens were reinforced at both ends by means of tabs which were bonded on both faces to reduce the effects of the external pressure exerted on them through the grips of the testing machines, and the rest of them were tested without any reinforcement tabs. All the specimens were tested until failure. Load, elongation (displacement) and strain data were recorded by means of strain gages and data acquisition systems. The experimental results obtained from similar tests on different groups are compared to examine the conformity of the results regardless of dimension and geometry, and are also verified by Finite Element Analysis (FEA). In addition, FEA is used to study different conditions, such as geometry, that could affect the final results. The experimental data are analyzed and effects of fiber direction on failure method are studied. It was concluded that shape and geometry factors as well as fiber direction influenced the failure method. The work, however, is still in progress and tests under conditions, such as elevated temperature, will be conducted to study other effects on the mechanical properties of 3D woven carbon-epoxy composites.