Investigation of the Design Parameters and Its Response Spectrum of a Shock Generator
Date Issued
2009
Date
2009
Author(s)
Chen, Huan-Zhang
Abstract
Electronic components often demand impact certifications prior to mass production. The purpose of fulfilling impact test is to prevent component failures in various working environments. Typical half-sine or rectangular wave is employed as the shock pulse to simulate the shock in the real environment. Unfortunately, lots of shock waves are not so easily to carry out. They often consist of waves with various amplitudes over a wide span of frequencies. Consequently, the more general and accepted method in shock rests is the so-called Shock Response Spectrum (SRS). The essential of the SRS method is to model the shock system as a simple damped-spring-mass system of one degree-of-freedom. This dynamic system will response to a particular shock excitation with a maximum acceleration. The spectrum of the maximum accelerations for various natural frequencies of the system constitutes the SRS. If we can design a shock generator with its SRS covered the SRS of a real impact environment, then the cost and complexity of an impact facility can be largely reduced. Recently, Dr. Min-Han Chiu had developed an explosion-driven shock apparatus (called shock generator) which made the use of energetic material as the energy source at very low cost. The generator can even meet the condition G listed in MIL-STD-883E. However, experiments show that the apparatus broke down at the rod corner just after two test runs. Numerical simulations also evidence the existence of several over-stresses regions in the test rig. The simple and yet low cost shock generator deserves further improved design of its key dimensions, and hence its reliability, due to its possible wide applications. This thesis explores dimension parameters which influence the performances of the shock generator via numerical simulation. The software, ANSYS LS-DYNA, was used to compute the dynamic response of the system with various geometries subjected to the designated impact sources. The improved design of the shock generator would provide better performance and reliability than the original one. Moreover, this investigation will propose a precise amount of the explosive to drive the shock generator according to various shock specifications described in MIL-STD 883E.
Subjects
shock response
shock conditions
LS-DYNA
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-R96543028-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):59024d82127dcca13a3c16c68bda3f65