Compressive behavior of non-slender hollow GFRP structural shapes in thermomechanical loading
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- 作者：Yail J. Kim ; jimmy.kim@ucdenver.edu ; Kenny Zongxi Qian
- 关键词：Axial compression ; Column ; Composite ; Glass fiber reinforced polymer (GFRP) ; Pultruded shape ; Thermomechanics
- 刊名：Composite Structures
- 出版年：2017
- 出版时间：15 January 2017
- 年：2017
- 卷：160
- 期：Complete
- 页码：813-823
- 全文大小：2933 K
- 卷排序：160
文摘
This paper presents an experimental study of the thermomechanical behavior of hollow square columns made of pultruded glass fiber reinforced polymer (GFRP). The specimens are subjected to monotonic and cyclic loadings until compression failure occurs in conjunction with elevated temperatures ranging from 25 to 175 °C. The twofold investigation emphasizes material- and structure-level responses, including dynamic mechanical analysis, constitutive behavior, load-carrying capacity, and failure mode. GFRP phase transitions (from elastic to plastic) due to thermal distress influence displacement compatibility at the boundary between the fibers and resin. Consequently, the stress-strain behavior changes from linear to bilinear ascending, accompanied by discrete composite-rupture and scattered fiber-tearing failure modes, depending upon temperature exposure. With respect to the capacity of the columns, the effect of the monotonic and cyclic loadings is marginal regardless of temperature. By contrast, the specimens subjected to cyclic loading show a higher coefficient of variation in comparison with those tested monotonically. With an increase in temperature, the location of primary failure shifts from the bolted connection in the vicinity of the support toward the middle of the column, which is attributable to minor lateral translation of the column induced by the thermally weakened resin. Using a probability-based model, a temperature-dependent capacity reduction factor is proposed. The alteration of functional probability-domains in thermomechanically-loaded columns is examined based on an uncertainty quantification method (i.e., metric distance measure).