An extensive study of into the static loading response and low-velocity impact response of plain and stiffened CFRP panels was conducted. The study investigated the impact response of the CFRP panels over a range of impact energies that include incident kinetic energies sufficiently high to cause complete penetration of the panel by the impacting mass. Static tests were also conducted by driving a hemispherical-nosed indentor into the panel up to displacements that resulted in the complete penetration of the panel by the indentor. Results from these tests suggest that the static perforation energy could predict the impact perforation energy with reasonable accuracy. A lumped-parameter mass-spring-damper model that attempted to incorporate the effects of material damage to the panel response was developed. The model was found to be sufficiently accurate in predicting the response of thin panels to static and impact loads up to the critical delamination force threshold. Assessment of the damaged panels through Penetrant-Enhanced X-Ray methods led to the identification of damage transition energy thresholds that differentiate between changes in damage mechanism. The damage transition energy thresholds were found to be constant fractions of the impact perforation energy.

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This thesis describes a study into the action of geotextiles in providing combined drainage and reinforcement to cohesive soil and the identification of the interaction of different geotextiles with a cohesive soil. The study involved both experimental and analytical investigations. Fine grained cohesive soil is a complex material. The introduction of geosynthetics providing both drainage and a reinforcement function produce a marked increase in the shear strength characteristics of the clay material. A number of consolidated undrained and consolidated drained triaxial compression tests and Rowe cell consolidation tests were conducted. The objective of the tests was to identify the separate effects (improvement) on the shear strength properties of the cohesive soil (kaolin) provided by the drainage function and separately that provided by the reinforcing function of a number of geotextiles. An Electron Scanning Microscope study was used to investigate the interaction between the cohesive soil and the geosynthetic materials. The study provided qualitative information concerning the relative improvement of the physical properties of a fine grained cohesive soil when used in construction with range of geosynthetic materials. Analysis of the results of the research suggest that geotextile products could offer significant technical, practical and economic advantages when constructed with poor quality soils. The combined function of drainage and reinforcement which could be developed by some geosynthetic materials could be substantial. Combining the functions of drainage and reinforcement in a single material requires the resulting geosynthetic to have special properties. The form of a geocomposite drainage and reinforcement material with these properties is proposed

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Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 94-97). / xi, 97 leaves, bound ill. (some col.) 29 cm