Modeling of Ordnance-Induced Pyrotechnic Shock Testing
Design of an ordnance-induced pyrotechnic shock test to meet a specific acceleration based Shock Response Spectrum (SRS) test requirement for a given test article has traditionally been an empirical process. Based on experience, the test engineer will determine a potential test configuration and then, through a trial-and-error process, modify the test parameters and configuration until acceptable SRS levels have been achieved. As a complement to this approach, National Technical Systems (NTS) has developed an explicit finite element based modeling approach to simulate an ordnance-induced pyrotechnic shock test. This tool may be used to assist with test configuration design for particularly challenging test requirements or to streamline the process of arriving at acceptable test levels during the calibration phase of a test program.
Development of a miniature point source pyroshock simulator
Abstract Pyrotechnic devices have been widely utilized in various applications: spacecraft, launch vehicles, missiles, and aircraft as well as for stage separation, valve control, and booster separation. However, most pyrotechnic separators generate an intensive mechanical transient response called pyroshock, which can cause catastrophic failures in electronic equipment. In order to validate that the structure or equipment can withstand the generated shock level, pyroshock tests should be performed with properly simulated structural configurations and the shock sources. Most of the previous pyroshock simulators using mechanical excitation have been developed as shock table configurations; they can effectively apply the target shock levels to the test component. However, it is difficult to simulate the pyroshock source in practical structures. In this study, a miniature pyroshock simulator that can easily replace a pyrotechnic device and is adaptable onto the most practical structures was developed. A disk resonator is introduced to control the shock response by changing the first natural frequency of the disk resonator. To excite the disk resonator, we devised a launch device that effectively controls the impact velocity with easy reloading capability. Experiments for 27 different conditions were conducted to identify the control parameters for the shock levels. The developed simulator also showed high repeatability, and it is easy to prepare repeated experiments using the developed shock simulator. This device can easily generate the simulated point-source pyroshock for real structures such as an assembled spacecraft.
Degradable polymers : principles and applications
1. Why Biodegradable Polymers? G. Scott. 2. An Overview of Biodegradable Polymers and Biodegradation of Polymers S.H. Huang. 3. Degradation and Stabilization of Carbon-Chain Polymers G. Scott. 4. Techniques and Methods of Polymer Degradation S. Karlsson, A.-C. Albertsson. 5. Biodegradation of Aliphatic Polyesters Suming Li, M. Vert. 6. Starch-Polymer Composites C. Bastioli. 7. Polymers from Renewable Sources E. Chiellini, et al. 8. Sustainable Poly(Hydroxyalkanoate) (PHA) Production G. Braunegg. 9. Polyhydroxyalkanoates: Properties and Modification for High Volume Application I. Chodak. 10. Biodegradable Polymers in Medicine E Piskin. 11. Environmentally Biodegradable Water-Soluble Polymers G. Swift. 12. Plastics and the Environment J. Guillet. 13. Degradable Hydrocarbon Polymers in Waste and Litter Control G. Scott, D.M. Wiles. Subject Index.