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Date of Award
Campus Access Master's Report
Master of Science in Mechanical Engineering (MS)
Administrative Home Department
Department of Mechanical Engineering-Engineering Mechanics
Gregory M. Odegard
Committee Member 1
Committee Member 2
REL Inc. and Michigan Tech have jointly designed a conformable CNG tank to meet the requirements of long range travel using CNG powered engines, without compromising on the cargo space. To pass the product validation, this tank must pass the NGV2 drop test. Physical drop tests have confirmed satisfactory compliance with NGV2 drop test. It is required to be able to FEA simulate the drop test as close to reality as possible so that design predictions can be made for the next stage of the tank which is called phase two. This report aims at establishing general guidelines for simulating a drop test using HyperMesh/RADIOSS, by analyzing the various simulation parameters and their effect on the drop test results. The material model used for representing the Aluminum alloy tank is Johnson Cook (LAW2 in RADIOSS). This report explains the process of obtaining the Johnson Cook parameters from the stress strain curve and applying them in RADIOSS. This report also discusses other important simulation parameters like co-efficient of friction between the contact areas, as well as the effect of representing the Johnson Cook stress-strain curve by a bi-linear piecewise linear model. Another important aspect of this study is analyzing the various idealizations of the ground on which the drop test is simulated. The idealizations considered were 2D rigid wall, 3D slab with dimensions corresponding to actual slab and possibility of restricting the bottom face for the degrees of freedom. Conclusions are drawn based on the current limitations with using RADIOSS, and what recommendations can be made for better simulation of the drop test.
Bongir, Sumit Shekhar, "Drop Test Simulation of a Conformable CNG Tank by Finite Element Analysis using HyperMesh/RADIOSS", Campus Access Master's Report, Michigan Technological University, 2016.