Recently, there is an increasing demand for a method of fixing materials used in automobiles and buildings with structural adhesives to various composites materials (CFRP, aluminum, iron, etc.) in order to reduce weight and enhance functionality. This method has the advantage of being able to combine various complex performances that cannot be obtained in the existing method compared to the traditional method of mechanically combining a single material using bolts, rivets, etc., but each physical performance of various materials Since different physical properties may occur for each material used in various environmental and physical stresses that may occur from the outside, there is a risk of causing a decrease in overall performance and long-term durability and securing safety.
However, the application of composites materials can overcome the limitations of existing single materials, secure complex performance such as lightness and insulation, and provide various benefits such as production cost and energy reduction, if only reliability for service life is secured in such a real environment. Because of the advantages, interest and demand are expanding, especially in the field of mobility industries such as automobiles and aviation.
The composition of composites materials can be designed in various forms depending on the materials used, such as metals, non-ferrous metals, polymers, and composite materials. As a representative example, in the case of composites materials using metals and polymers, high temperature, low temperature, humidity and fatigue load in outdoor environments, etc. As physicochemical defects occur and grow due to the difference in thermal performance and physical deformation of different materials due to the complex stress of different materials, and the decrease in service life occurs, in this paper, I would like to study to predicts the service life under these complex environment conditions and assessment reliability. and I would like to describe a method to secure the reliability of composites materials by preparing a test method that can be guaranteed.
In this study, a test piece attached with a structural adhesive to a composites material composed of iron and CFRP was fabricated, and the temperature at which the inflection point of mechanical properties occurs and the glass transition temperature were analyzed through thermal analysis, and according to the temperature of the adhesive test piece any correlation with the change in physical properties was compared.
In addition, the relationship between temperature and lifetime was analyzed through the Arrhenius model for the activation energy and the shape parameter of the Weibull distribution, and the acceleration factor due to temperature stress was obtained to analyze the life prediction by the accelerated life test.