KY Space Grant REU-22-010: Experimental Characterization and Constitutive Modeling of an Aircraft Grade Aluminum Alloy Sheet

The proposed research activity aims to conduct experimental characterization and constitutive modeling of an aircraft grade 7075 aluminum alloy sheet (AA 7075). It is one of the most widely used aluminum alloys in aircraft structural parts subjected to high stresses. Due to its excellent mechanical properties such as high strength, ductility, toughness, and resistance to fatigue, AA 7075 has a great potential for extensive use in spacecraft structures for NASA space missions. Many studies have been carried out in understanding and modeling the responses of AA 7075 alloys based on the uniaxial response of the material. However, there has been a limited study in understanding the anisotropic and complex material behavior under multiaxial response resulting in lack of adequate parameters required to formulate a constitutive model. In this project, the material behavior will be comprehensively characterized using mechanical testing scheme employing both uniaxial and multiaxial responses. From these tests, a diverse number of parameters will be adequately quantified for the governing equations of the adopted constitutive model. This properly calibrated constitutive model can describe the material response to different mechanical loading condition at different orientations with respect to the major material direction. The effectiveness of constitutive model plays a key role in the predictive capabilities of computational models and numerical simulations of structures. This study would enhance the understanding of material behavior of this alloy and aid in the design and optimization of aircraft and spacecraft structural parts.