Grant: Discovery Grants Program - Individual

Composite sandwich panels are increasingly used in many applications such as space structures, naval structures, wind turbines, aircraft, etc. In all of these applications, they are subjected to cyclic environmental conditions which leads to the development of internal stresses at different scales caused by the anisotropy and heterogeneity of composite structures. The cyclic nature of these internal stresses can in turn lead to damage development. Temperature and humidity also influence the mechanical properties and the fracture behavior of sandwich panels constituents. Large time and money investments are required to develop composite structures. Because of that, industries are turning to numerical simulations and virtual testing. The principle behind virtual testing is that each experimental test required for the development of a composite structure, starting at the coupon scale and evolving toward large scale testing, can all be performed virtually using numerical simulations. Testing in various experimental conditions is part of the development of composite structures and thus could be integrated to the virtual testing method. The long-term goal of the proposed research program is to integrate the effects of environmental conditions on the mechanical behavior of composite structures to the virtual testing process. In order to do so, a better understanding of the effect of temperature on composite structures and their constituents and the development of numerical tools are required. For now, the research program is focused on the effect of temperature, but will, in the future, include the effect of other environmental conditions such as humidity. As a starting point, the project is developed around composite sandwich panels as the main type of structures studied. However, because the research program aims to look at the multiscale nature of the phenomena caused by temperature changes, laminates, cores and composite assemblies are also part of the proposed research program. The research program is centered around a fairly large long-term goal. Thus, three short-term objectives have been identified in the pursuit of the main research goal: ?Evaluation of thermal cycles effects on the damage development and the mechanical behavior of composite sandwich panels and assemblies; ?Multiscale evaluation of thermally induced stresses in composite sandwich panels and assemblies; ?Experimental and numerical investigation of the effect of temperature on the mechanical behavior of Nomex honeycomb cores towards the development of a predictive tool. The proposed research program will contribute to a deeper understanding of physical phenomena encountered by composite sandwich panels subjected to various environmental conditions by studying the multiscale nature of these phenomena. The outcomes of the research program will contribute to the development of numerical tools that will facilitate the design of composite sandwich parts.