Low velocity dropweight impact tests were conducted on carbon/epoxy laminates under various boundary conditions. The composite plates were 8-ply (+45,0, -45,90)s laminates supported in a clamped-clamped/free-free configuration with varying amounts of in-plane load, N(sub x), applied. Specimens were impacted at energies of 3.4, 4.5, and 6 Joules (2.5, 3.3, and 4.4 ft-lb). The amount of damage induced into the specimen was evaluated using instrumented impact techniques, x-ray inspection, and cross-sectional photomicroscopy. Some static identation tests were performed to examine if the impact events utilized in this study were of a quasi-static nature and also to gain insight into the shape of the deflected surface at various impact load combinations. Load-displacement curves from these tests were compared to those of the impact tests, as was damage determined from x-ray inspection. The finite element technique was used to model the impact event and determine the stress field within the laminae. Results showed that for a given impact energy level, more damage was induced into the specimen as the external in-plane load, N(sub x), was increased. The majority of damage observed consisted of back face splitting of the matrix parallel to the fibers in that ply, associated with delaminations emanating from these splits. The analysis showed qualitatively the results of impact conditions on maximum load of impact, maximum transverse deflection, and first failure mode and location. Nettles, A. T. and Hodge, A. J. Marshall Space Flight Center EPOXY MATRIX COMPOSITES; LAMINATES; IMPACT TESTS; DYNAMIC TESTS; X RAY INSPECTION; STRESS DISTRIBUTION; PLATES (STRUCTURAL MEMBERS); LOADS (FORCES); FAILURE MODES; DISPLACEMENT; DEFLECTION; DAMAGE; BOUNDARY CONDITION

A respected resource for decades, the Guide for the Care and Use of Laboratory Animals has been updated by a committee of experts, taking into consideration input from the scientific and laboratory animal communities and the public at large. The Guide incorporates new scientific information on common laboratory animals, including aquatic species, and includes extensive references. It is organized around major components of animal use: Key concepts of animal care and use. The Guide sets the framework for the humane care and use of laboratory animals. Animal care and use program. The Guide discusses the concept of a broad Program of Animal Care and Use, including roles and responsibilities of the Institutional Official, Attending Veterinarian and the Institutional Animal Care and Use Committee. Animal environment, husbandry, and management. A chapter on this topic is now divided into sections on terrestrial and aquatic animals and provides recommendations for housing and environment, husbandry, behavioral and population management, and more. Veterinary care. The Guide discusses veterinary care and the responsibilities of the Attending Veterinarian. It includes recommendations on animal procurement and transportation, preventive medicine (including animal biosecurity), and clinical care and management. The Guide addresses distress and pain recognition and relief, and issues surrounding euthanasia. Physical plant. The Guide identifies design issues, providing construction guidelines for functional areas; considerations such as drainage, vibration and noise control, and environmental monitoring; and specialized facilities for animal housing and research needs. The Guide for the Care and Use of Laboratory Animals provides a framework for the judgments required in the management of animal facilities. This updated and expanded resource of proven value will be important to scientists and researchers, veterinarians, animal care personnel, facilities managers, institutional administrators, policy makers involved in research issues, and animal welfare advocates.

Dynamic Deformation, Damage and Fracture in Composite Materials and Structures, Second Edition reviews various aspects of dynamic deformation, damage and fracture, mostly in composite laminates and sandwich structures, and in a broad range of application areas including aerospace, automotive, defense and sports engineering. This book examines low- and high-velocity loading and assesses shock, blast and penetrative events, and has been updated to cover important new developments such as the use of additive manufacturing to produce composites, including fiber-reinforced ones. New microstructural, experimental, theoretical, and numerical studies with advanced tools are included as well. The book also features four new chapters covering topics such as dynamic delamination, dynamic deformation and fracture in 3D-printed composites, ballistic impacts with fragmenting projectiles, and the effect of multiple impacting. - Examines dynamic deformation and fracture of composite materials, covering experimental, analytical and numerical aspects - Features four new chapters covering topics such as dynamic interfacial fracture, fracture in 3D-printed composites, ballistic impacts with fragmenting projectiles, and the effect of multiple impacting - Addresses important application areas such as aerospace, automotive, wind energy, defense and sports