Flexural Properties of Brittle Multilayer Materials: II, Experiments
Flexural Properties of Brittle Multilayer Materials: II, Experiments
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DOI：
10.1111/j.1151-2916.1994.tb07100.x
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发表时间：
1994-08
影响因子：
3.9
通讯作者：
C. Folsom;F. Zok;F. Lange
中科院分区：
文献类型：
--
作者：
C. Folsom;F. Zok;F. Lange
对多种脆性多层膜材料的弯曲性能进行了实验研究。结果与一篇论文中提出的模型的预测结果进行了比较。研究了三种类型的系统。第一种是用热塑性粘合剂粘合在一起的玻璃片。玻璃板在粘合之前通过压痕预裂，因此它们的强度基本上是确定的。该体系的弯曲响应以初始线弹性区为特征，然后在开裂过程中应力-应变曲线逐渐减小。第二个系统由薄玻璃片(没有凹痕)组成，也用热塑性粘合剂粘合在一起。该系统表现出与具有凹槽玻璃板的系统相似的弯曲特性。在这两个系统中，测量的应力-应变行为与模型预测的结果吻合得很好，包含了组成层的强度特征。第三种体系是一种混杂复合材料，由脆性相(玻璃或氧化铝)和碳纤维增强的环氧基复合材料交替层组成。这些系统表现出初始线弹性响应，随后在每个脆性层中形成多个裂纹的区域，除了压缩面上的一个裂纹。这一过程通常是在逐渐增加的压力下发生的。在这一阶段，没有一层纤维增强层失效。峰值应力与纤维增强层的破坏开始时间相吻合。这些层的渐进性破坏伴随着阶梯状的载荷下降，类似于在单相玻璃多层样品中观察到的情况。这些系统的测量响应与模型预测定性一致，但也注意到了一些差异，并简要讨论了它们的来源。
An experimental investigation of the flexural properties of a variety of brittle multilayer materials has been conducted. The results have been compared with the predictions of a model presented in a companion paper. Three types of systems have been studied. The first consisted of glass sheets bonded together with a thermoplastic adhesive. The glass sheets had been precracked by indentation prior to bonding such that their strengths were essentially deterministic. The flexural response of this system is characterized by an initial linear elastic regime, followed by a stepwise reduction in the stress–strain curve during cracking. The second system consisted of thin glass sheets (without indents), also bonded with a thermoplastic adhesive. This system exhibited flexural characteristics similar to those found in the system with indented glass plates. In both systems, the measured stress–strain behavior was in good agreement with the model predictions, incorporating the strength characteristics of the constituent layers. The third type of system was a hybrid composite comprised of alternating layers of a brittle phase (either glass or Al2O3) and a carbon-fiber-reinforced epoxy composite. These systems exhibited an initial linear elastic response, followed by a regime in which multiple cracks formed in each of the brittle layers, with the exception of the one on the compressive face. This process generally occurred subject to a progressively increasing stress. None of the fiber-reinforced layers failed during this stage. The peak stress coincided with the onset of failure of the fiber-reinforced layers. The progressive failure of these layers was accompanied by steplike load drops, similar to those observed in the single-phase glass multilayer specimens. The measured response of these systems was qualitatively consistent with the model predictions, though some discrepancies have been noted and their origins briefly discussed.