Effects of low temperature on the dynamic moduli of thick composite beams with absorbed moisture

✍ Scribed by K.H. Ip; P.K. Dutta; D. Hui

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 226 KB
• Volume: 32
• Category: Article
• ISSN: 1359-8368
• DOI: 10.1016/s1359-8368(01)00037-3

✦ Synopsis

The present investigation concentrates on the in¯uence of low temperature and moisture on the dynamic moduli of thick S2-glass composite beams. By supporting the beam sample in a free±free con®guration, its natural frequencies were obtained through impact testing. Frequency dependence on the hydrothermal conditions was disclosed by testing the sample at different temperatures and with different moisture contents. Based on the frequency measurements, a method was developed to predict the longitudinal Young's modulus and the transverse shear modulus of the sample. The process involves iterative tuning of the moduli of a Timoshenko beam model via a stable characterization scheme. Numerical sensitivity study shows that the moduli thus determined are insensitive to measurement errors rendering the method a possible supplement for conventional static tests. Both frequencies and moduli of the beam sample were found to exhibit an increasing trend with reducing temperature. Besides, freezing of the absorbed moisture enlarged the longitudinal Young's modulus of the material in a signi®cant manner.