Crack initiation, propagation and strain mapping during composite bending using digital image correlation and theoretical calculations

IF 7.1 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures Pub Date : 2025-09-18 DOI:10.1016/j.compstruct.2025.119680

Karolina Głowacka , Tadeusz Smolnicki

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引用次数: 0

Abstract

The study focuses on analyzing strains and stresses in bent specimens of various dimensions. Depending on the maximum normal to shear stress ratio during bending, two failure modes can occur: translaminar and interlaminar. A higher value of this ratio increases the likelihood of translaminar failure. The research demonstrates that the critical value for polypropylene reinforced with unidirectional continuous glass fibers is 24. In this case, specimens exhibited both translaminar and interlaminar failure modes. The study also examined the specimens’ appearance at different stages of the bending test, as well as their microstructure after failure. Digital image correlation (DIC) was employed, enabling the determination of strain values for individual specimens and the comparison of theoretical values with those obtained experimentally via DIC. It was found that while the linear strain along the fibers and the shear strain were consistent, the actual strain across the specimen’s height was significantly higher than the theoretically calculated value. This discrepancy is likely due to the occurrence of additional stresses within the specimen, particularly associated with Hertzian contact phenomena, which caused localized compression and further influenced the strain distribution.

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基于数字图像相关和理论计算的复合材料弯曲裂纹萌生、扩展和应变映射

研究的重点是分析不同尺寸弯曲试样的应变和应力。根据弯曲过程中最大法向与剪应力比的不同，可以发生两种破坏模式：跨层破坏和层间破坏。该比值越高，椎板间破裂的可能性越大。研究表明，单向连续玻璃纤维增强聚丙烯的临界值为24。在这种情况下，试件表现出跨层和层间两种破坏模式。研究还考察了试件在弯曲试验不同阶段的外观，以及破坏后的微观结构。采用数字图像相关（DIC），可以确定单个试样的应变值，并将理论值与DIC实验值进行比较。结果表明，虽然沿纤维方向的线应变与剪切应变一致，但沿试件高度方向的实际应变明显高于理论计算值。这种差异可能是由于试样内部发生额外应力，特别是与赫兹接触现象有关，造成局部压缩，进一步影响应变分布。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Composite Structures 工程技术-材料科学：复合

CiteScore

12.00

自引率

12.70%

发文量

1246

审稿时长

78 days

期刊介绍： The past few decades have seen outstanding advances in the use of composite materials in structural applications. There can be little doubt that, within engineering circles, composites have revolutionised traditional design concepts and made possible an unparalleled range of new and exciting possibilities as viable materials for construction. Composite Structures, an International Journal, disseminates knowledge between users, manufacturers, designers and researchers involved in structures or structural components manufactured using composite materials. The journal publishes papers which contribute to knowledge in the use of composite materials in engineering structures. Papers deal with design, research and development studies, experimental investigations, theoretical analysis and fabrication techniques relevant to the application of composites in load-bearing components for assemblies, ranging from individual components such as plates and shells to complete composite structures.