複合材料積層板與應變率有關之非線性行為

Abstract

本研究在建立一理論模型以描述複合材料積層板於不同應變率下其非線性的應力-應變關係。利用單參數塑性能導入流速定理，來建立單方向複合材料在不同應變率下機械行為之黏塑性模型。而此一黏塑性模型係利用冪次函數型式之有效應力-有效塑性應變曲線表示之。結合古典積層板理論，並考慮在積層板各層中之熱殘餘應力，延伸此黏塑性模型，以預測複合材料層板隨應變率變化之非線性行為。將對稱的玻纖/環氧樹脂複合積層板與碳纖/環氧樹脂複合積層板，在三個不同之應變率( 0.0001/秒，0.01/秒，與1/秒) 下作拉伸試驗，用以和理論模型預測比對。

The study aims to investigate and model the strain rate effect on the nonlinear behaviors of composite laminates. The viscoplasticity model proposed for describing the nonlinear rate-dependent behavior of unidirectional composites was employed together with the laminated plate theory to model the rate sensitivity of the composite laminates. It was also considered the thermal residual stress in each ply of laminate. Using one parameter plastic potential to describe the flow rule, this viscoplasticity model was expressed as a single master effective stress-effective plastic strain curve which can be expressed in the form of power law. Two composite laminate materials, symmetric glass/epoxy laminates and symmetric graphite/epoxy laminates, were tested at three stain rates of 0.0001/s, 0.01/s and 1/s respectively and the experimental results were then compared with the model predictions.