Date of Award
Master of Science in Civil Engineering (MSCE)
Committee Member 1
Committee Member 2
Numerous engineering applications involve one or more mechanical components that come into contact with each other during operation. Repetitive motions under contact can lead to fatigue and wear problems in the components. When designing such components, it is important to characterize and quantify the stresses and strains in the contacting elements. This can be achieved by numerical simulation of the process and by using one of the several contact formulations available in most finite element software programs. However, contact is an inherently non-linear problem which is rather challenging even for the best commercial software programs currently available. Often contact simulations are plagued by issues of high computational cost and non-convergence that are highly problem dependent. Further, modeling approaches that work for one scenario do not generalize easily for other problems.
In several applications, one encounters sliding contact that is persistent. In such cases, components always stay in contact during operation but slide with respect to one another within a small range of motion. An example of such an application is the interlock hose where thin strips of sheet metal are coiled together in a way that adjacent coils lock with each other to form a flexible hose. This flexible hose allows a limited amount of motion between adjacent coils by letting the coils slide with respect to each other while always remaining in locked contact.
In this study, a simplified model is developed for applications with persistent sliding contact. The simplified model utilizes slender spring and membrane elements that are stiff in the direction of their orientation but flexible in the transverse direction. The stiff response is used to simulate persistent contact and to prevent gaps or penetration between contacting components and the flexible response is used to create a bi-stable mechanism that mimics sliding between the components. The primary benefit of this approach is that it is far more computationally efficient than conventional approaches for modeling contact with high fidelity. However, given that it is a simplified model, one loses some accuracy in the solution, especially in regions of the model that are actually in contact. Nevertheless, this simplified approach and conventional high-fidelity contact models produce deformations and stresses that are very similar in parts of the model that are away from the immediate region of contact. Several numerical examples are presented to illustrate the simplified model and to compare its performance, both in terms of solution accuracy and computational cost, to conventional high-fidelity contact models.
Patil, Adarsh, "Simplified model for persistent sliding contact" (2017). Open Access Theses. 1314.