ansys分随机振动.doc

Random Vibration Analysis with ANSYS and Verification By Ye Zhou May 2002 Table of Contents TOC \o 2-3 1 Introduction to Random Vibration PAGEREF _To\h 3 1.1 Failure Modes in Random Vibration PAGEREF _To\h 3 1.2 Random Vibration Input Curve and Units PAGEREF _To\h 3 1.3 Normal Distribution Curve PAGEREF _To\h 4 1.4 PSD for Fatigue Calculation PAGEREF _To\h 5 2 Formulation PAGEREF _To\h 7 2.1 Steinberg formulation [1. 9.16]: PAGEREF _To\h 7 2.2 Thomson formulation [2. 10.3]: PAGEREF _To\h 8 2.3 Newland formulation [4. 7]: PAGEREF _To\h 8 3 ANSYS Procedures PAGEREF _To\h 10 4 References PAGEREF _To\h 12 5 Appendix – ANSYS PSD Input/Output File PAGEREF _To\h 13 5.1 Input File PAGEREF _To\h 13 5.2 Output File PAGEREF _To\h 15 List of Figures TOC \z \c Figure Figure 1 Typical white noise curve with a constant input power spectral density (PSD) PAGEREF _To\h 4 Figure 2 Sample 1-DOF model PAGEREF _To\h 7 Figure 3 ANSYS calculated output PSD PAGEREF _To\h 10 List of Tables TOC \z \c Table Table 1 Type of spectral densities PAGEREF _To\h 4 Table 2 Safety index/sigma values used in building codes PAGEREF _To\h 5 Table 3 ANSYS results verification PAGEREF _To\h 10 Table 4 ANSYS PSD result load steps PAGEREF _To\h 11 Introduction to Random Vibration Random vibration is being specified for acceptance and qualification tests by many institutions, because it has been shown that random vibration more closely represents the true environments in which the structures and equipment must operate. Failure Modes in Random Vibration There are four basic failure modes that must be considered under random vibration. These failures are: High acceleration levels. High stress levels. Large displacement amplitudes. Electrical signals out of tolerance (electric