Abstract Pseudo-ductility could be sought in composite structures to avoid their brittle behaviour and, consequently, to withstand higher levels of external loading due to an extended non-linear response. This mechanism has been deeply examined in the literature for angle-ply laminates submitted to uniaxial tests. Nonetheless, the pseudo-ductile effects could appear also under flexural loading because tension and compression are applied in different regions of the cross-sections simultaneously. In this sense, bending testing presents a higher degree of complexity introduced by the variation of the strain through the cross-section thickness. Taking this into account the main scope of this work is to understand, describe, predict and optimise the pseudo-ductile flexural response of symmetric ±45° angle-ply laminates consisting of unidirectional and continuous CFRP plies. The outcome of three-point bending tests is reviewed analytically and experimentally. The analytical study considers the different behaviour of the material under tension and compression as well as the neutral fibre deviation from the mid-height plane. During testing the full normal strain field is acquired by means of a DIC system while strain-rosettes help to complete the data. The post-process based on microscopic characterization using SEM technology allows to observe the procedure of damage initiation and its evolution. Finally, the determination of the stacking sequences that minimise the bending-twisting coupling but favour the pseudo-ductile response is developed applying optimisation techniques with design purposes.

中文翻译：

---

对称 ±45° 角层 CFRP 层压板弯曲试验中的伪延展性

摘要 可以在复合结构中寻求伪延展性，以避免它们的脆性行为，因此，由于扩展的非线性响应，可以承受更高水平的外部载荷。这种机制已在提交单轴测试的角层层压板的文献中进行了深入研究。尽管如此，由于拉伸和压缩同时施加在横截面的不同区域，因此在弯曲载荷下也可能出现伪延性效应。从这个意义上说，弯曲测试呈现出更高程度的复杂性，这是由通过横截面厚度的应变变化引起的。考虑到这一点，这项工作的主要范围是理解、描述、预测和优化由单向和连续 CFRP 层组成的对称 ±45° 角层合板的伪延展弯曲响应。三点弯曲试验的结果通过分析和实验进行了审查。分析研究考虑了材料在拉伸和压缩下的不同行为以及中性纤维与中间高度平面的偏差。在测试过程中，通过 DIC 系统获取完整的法向应变场，而应变花环有助于完成数据。基于使用 SEM 技术的微观表征的后处理允许观察损伤起始及其演变过程。最后，