نظارت بر روی کامپوزیت های مبتنی بر بازالت تحت آزمون های ضربه ای
Abstract
1- Introduction
2- Experimental
3- Data analysis and discussion
4- Conclusions
References
Abstract
Scope of the present work is to visualize with infrared thermography the impact damaging of basalt-based composites. Two types of specimens are prepared with basalt fibres embedded in a polypropylene (PP) matrix, which is used either pure, or modified with the addition of a coupling agent. The latter improves the fibre/matrix interface strength providing in practice a material of different characteristics. Specimens are impacted at low velocity/energy with a modified Charpy pendulum while the infrared camera views the surface opposite to the impacted one and records thermal images in time sequence. The acquired sequences are post-processed to obtain information which may be exploited for the material characterization. In particular, the attention is to identify initiation and propagation of the impact damage and the overall delamination extension, as well as to discriminate likely differences between grafted and un-grafted composites in their impact-reaction. As a main result, the effects of the specimen’s fixture on the damage extension are highlighted.
Introduction
The growing awareness towards the environment is demanding for environmentally friendly materials, so moving the attention from the petrochemical resources towards more natural ones. Within this scenario, basalt fibres are attracting consideration from the scientific community because they seem to be adequate as reinforcement of composites and to comply with the environment safeguard rules [1]. In fact, basalt is available in nature in volcanic rocks and can be reduced in fibres, which are well suited to be used as reinforcement of both thermoset and thermoplastic matrices to create different types of composite materials. Basalt fibres are ecologically pure and, unlike the conventional asbestos/glass ones, which can cause health hazards, are non-hazardous as they are spun with a diameter higher than 6 m [2]. In addition, abrasion of basalt only produces thick fibre fragments that pose no respiratory hazard, even if, as with most substances, care in its handling is recommended. Basalt fibres are non-reactive toward water and do not cause air pollution and have a wide spectrum of applications. They are mainly produced for structural and electro-technical purposes including electromagnetic shielding structures, automobiles, aircraft, ships and household appliance components [3-5].