جستجوی مقالات مرتبط با کلیدواژه « پدیده خودترمیمی » در نشریات گروه « مواد و متالورژی »

Crack creation in composites is one of the most common failure reasons of those materials. Engineers were inspired by self-healing action in biological systems and used this innovation for the healing of different kinds of materials such as composites. In this study, using the self-healing approaches, micro-crack and damage healing of a epoxy-glass fibers composite were under consideration. So one series of hollow glass fibers were used to fabricate self-healing mechanism. These hollow fibers were filled by one self-healing agent which is one two-part epoxy resin. After the creation of undetectable micro-cracks and damages and also their encounter with hollow fibers’ walls, these hollow glass fibers will crack and the self-healing agent in them would flow into damage area that after some time it repairs the damage. The ain of the present study was to investigate the effect of heating cycles over time is restored in the composite. So consecutive temperature cycles (1, 3 and 5 cycle) in temperature were implemented in the range of 25-70 °C after damage creation in the sample. The results of bending tests show that a 74% healing efficiency can be gained after 7 days almost with 5 cycles of heat in mentioned temperature range only after one day.

In the case of presence of deep micro-cracks within the composite structures, they must be replaced. The self-healing phenomenon which is inspired from the biological systems such as vascular networks in plants or capillary networks in animals is an appropriate strategy to control the defects and micro-cracks. In the present research, by taking accounts the advantages of self-healing concept, an attempt has been made to control the micro-cracks and damages which were created in composite structures. To do so, a series of micro glass tubes were employed to provide a self-healing system. These micro-tubes were filled with epoxy resin anhydride as a healing agent. When the structure is subjected to loading conditions, some damages or micro-cracks are created. In this situation, the micro glass tubes will rupture and the healing agent flows in the damage area, leading to the elimination of the defects over a time span. The aim of this study is to find out the appropriate micro glass tubes volume fraction and healing time to obtain an efficient healing. For this purpose, glass micro-tubes containing various anhydride agent loadings of 2, 4 and 6 vol. % were incorporated in epoxy-carbon fibers composites and the bending behavior of the specimens were assessed during different time span from defect creation. The highest bending strength recovery of 84% was observed for the specimen with 4% healing agent after 8 days