Research Proposal for Multistage Fatigue Model of AlMg Alloy using ICME
This proposal is the research map using Integrated Computational Materials Engineering (ICME) methods to see how Aluminum-Magnesium alloy will react in a multistage fatigue model. The product being tested is an arch wedge support. These are used to help correct the medial longitudinal arch in the foot and reduce injuries to the lower extremities of the body. This paper will map out the scope of the project, its limitations, and the plan for doing the modeling.
The scope of the project is to look at how the arch wedge support will react to the human step and how much time it will take for it to fail. The project will be to use a multistage failure model as a starting point since this material has not been known to used this way before. The other unique aspect of the project is the product made using additive manufacturing which will inherently have flaws due to the process of additive manufacturing. This is important because additive manufacturing allows us to create the product with complex geometries. The data about the failure rate will also us to conduct a comparison study with currently marketed arch wedge supports and verify the new material acts the same or different. The product can then be used by different groups like athletes and military personal to last longer than their plastic counter parts and reduce cost.
The first part of the study is understanding how the human foot interact with current arch wedge supports. Looking at the interaction of the foot with the ground will set up what boundary conditions will be used before down scaling. The interesting part of this project is the manufacturing of arch wedge supports has largely remained unchanged since the mid-20th century. Simon Spooner wrote an article about the history of arch wedge design, arch wedge manufacturing, and the future of the industry (1). He talks about how people have conducted experiments comparing how additive manufacturing compares to traditional manufacturing. He compared the cost and effectiveness of both techniques. The article was written in 2016 but the author mentions that both studies were conducted in 2011 and that the technology has evolved so much that he considered these studies to be already out of date. The other part of the study is the material choice. Typically, arch wedge supports are made from plastics and the project looks at the use of metal. The hopeful outcome is that the metal will provide the same benefits but will perform last longer than the plastics.
Starting at the electronics scale, we use Denstsity FUnction Theory in help determining the modulus of elasticity to upscale to both the next level (atomistics) and the macroscale.
At this level, we can look for the crack tip driving force which is the how the crack will move through the material and how fast it will move.
Here we look at two different levels. The first level is look at how voids will form in the material to see where cracks will start. Then we move up to the next level at this scale and look at how the voids will grow and combine together.
At this level, we start looking the large crack growth to see how the material will fracture in the end. We use finite elements analysis to help in predicting the crack growth at this length scale.
(1) Simon Spooner. 3d Orthotic Printing: Fad Or Game Changer?. http://www.podiatrytoday.com/3d-orthotic-printing-fad-or-game-changer. Podiatry Today, Volume 29, Issue 12, December 2016