CRACK SHIELDING MECHANISMS OF INTERLAYERED EPOXY MATERIALS UNDER QUASI-STATIC AND FATIGUE LOADING

This research explores the capability of PEI and PVDF thermoplastic interlayers to arrest cracks in epoxy materials modified with short-glass fibers and core-shell rubber particles. It also investigates the effect of interlayer position, the number of interlayers, and the type of epoxy materials on the fracture performance under mode-I quasi-static fracture and fatigue loading in a single-edge-notch bending configuration. The quasi-static fracture results demonstrate that the thermoplastic-epoxy interface effectively arrests the initial crack and reinitiating the crack at the thermoplastic layer requires up to 2.5 times higher load than the crack initiation load of the pristine epoxies. Furthermore, the interlayered designs exhibit up to 43 times more energy absorption than their pristine counterparts, and the study captures the competing damage mechanisms and failure events using microscopic images, digital image correlation, and high-speed photography observations.

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Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan
2023
Conference paper

Abstract

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https://infoscience.epfl.ch/record/309435?ln=en

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Related concepts (32)

Related publications (36)

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Self-healing materials are artificial or synthetically created substances that have the built-in ability to automatically repair damages to themselves without any external diagnosis of the problem or human intervention. Generally, materials will degrade over time due to fatigue, environmental conditions, or damage incurred during operation. Cracks and other types of damage on a microscopic level have been shown to change thermal, electrical, and acoustical properties of materials, and the propagation of cracks can lead to eventual failure of the material.

Fatigue (material)

In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts of the fracture surface. The crack will continue to grow until it reaches a critical size, which occurs when the stress intensity factor of the crack exceeds the fracture toughness of the material, producing rapid propagation and typically complete fracture of the structure.

Failure cause

Failure causes are defects in design, process, quality, or part application, which are the underlying cause of a failure or which initiate a process which leads to failure. Where failure depends on the user of the product or process, then human error must be considered. A part failure mode is the way in which a component failed "functionally" on the component level. Often a part has only a few failure modes. For example, a relay may fail to open or close contacts on demand.

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