A. Deepa ¹, K. Padmanabhan ¹, G. Raghunadh ²

Affiliations
1 SMEC, VIT University, Vellore - 632014, Tamil Nadu, IN
2 School of Mechanical Engineering, VIT University, Vellore - 632014, Tamil Nadu, IN

Abstract

Objective: To find the effect of hygrothermal loading on CFRP and GFRP composite materials by finding the properties like capacitance, micro hardness, moisture diffusivity and area of fraction. Methods: Hand layup and vacuum bag methods were used for fabrication of composites. Finding: Three-point bending test was done on each specimen by varying load, i. e, zero load, with 30% load, 50% load and 70% load for different time periods. Micro hardness and capacitance were determined using Vickers Hardness tester and LCR meter respectively on both the composites before and after the thermal treatment. The capacitance increased with time whereas the percentage area of fraction of the fibre decreased. Also, the reduction in strength and damage to fibre were investigated using SEM. It was observed that with increase in %weight gain, micro hardness of specimen decreased. Application/Improvement: FRPs can substitute traditional steel reinforcements in reinforced concrete structures. The continuous loading under thermal actions due to natural environmental factors lead to degrading effect that needs to accurate investigations in evaluating durability of fibre reinforced polymers.

Keywords

Area of Fraction, Capacitance, Failure Modes, Hygrothermal Loading, Micro Hardness.

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D. Kumaran ¹, A. Rajadurai ², K. Padmanabhan ³

Affiliations
1 Department of Mechanical Engineering, SRM University, Chennai - 603203, Tamil Nadu, IN
2 Department of Production Technology, Madras Institute of Technology, Chennai - 600044, Tamil Nadu, IN
3 School of Mechanical and Building Sciences, VIT-University, Vellore - 632014, Tamil Nadu, IN

Abstract

Objectives: The present work reports the possible solution of using the high thermal stability polymer fibres with superior mechanical properties as that of, or, even better than metals for light weight applications like aerospace and automobile. Methods/Statistical Analysis: The PBO filament fibre was used as reinforcement. The PBO fibres were electroless copper coated to protect the polymer fibre from oxidation during processing and to improve the interfacial properties between the reinforcing polymer and the metal matrix. LM6 aluminium cast alloy was used as a matrix metal. The electroless copper coated PBO fibres preform were unidirectional placed inside a mould and infiltrated by molten liquid metal. Findings: After casting, it was found that the liquid melt could infiltrate only partially through the first layer of the fibre preform, and could not infiltrate further, which was evident from the infiltrated metal front. This was mainly because of the forced convective heat transfer made by the argon cover gas, which cools the molten metal front and thereby increases the surface tension of the advancing front. It was further noticed that some charring of the polymer fibres after two hours of casting, which reflects that, there was oxidation of polymer fibres after prolonged heating by the hot infiltrating metal front in absence of argon cover gas after first one hour of its use after casting. Application: The new material proposed for development could find applications in light weight high performance vehicles like aerospace and automobiles..

Keywords

Composites, High-Modulus, High-Strength, Metal-Matrix, Polymer, Reinforced

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