Failure Analysis of Hydraulic Hammer Tool by Finite Element Method.
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Date
2018
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Addis Ababa University
Abstract
The hydraulic hammers exposed to heavy-duty working condition occasionally generate premature failure of the tool. In actual case tool failure is caused by varies type of load. Under this thesis tensile stress developed on tool is considered for the investigation of tool failure. During rock breaking; both the axial and combined loading conditions mainly depend on thrust force acting on the tool. One particular existing design model H130ES hydraulic hammer tool is chosen for investigation of failure analysis. The dimensions, mechanical property and maximum hydraulic pressure are the input for both analytical and finite element method analysis. Using Finite Element Method with some analytical calculation this thesis tries to address the root causes responsible for tool failure. ANSYS 15 software is used as a strategic tool to perform each step in an orderly manner. The finite element simulation based on ANSYS identifies the maximum stress area and crack propagation simulation on tool. Analytically the stress concentration factor is solved as function of stress and assumed crack length. The analytical result is compared with FEM analysis. From the result obtained; the root cause of tool failure is an increase in thrust force on tool during rock breaking. To minimize such failure some recommendation is putted mainly with investigating tool manufacturing and design processes. Most important issue this thesis also addresses is the local problem of early tool failure caused by improper operation as well as lack of proper maintenance of hydraulic hammer.
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Keywords
Hydraulic Hammer, Failure Analysis, Finite Element Method