Fatigue Life Prediction For Small Component Welds
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Date
2022-07-24
Authors
Yusman, Muhammad Syafiq Farhan
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Almost all mechanical structures that adopts weld joints as connection method is
susceptible to fatigue failure when operating load is applied repeatedly. In semi-automatic
honeycomb cookies dipping machine, the weld components connecting
rose-shaped mould to the moulding frame becomes the most critical location in the
structure since the mould tend to be detached from the frame after long operational
time resulting in reduction of manufacturing quantity. The suspected causes of this
problem are due to vibration fatigue and thermal fatigue. Vibration fatigue is resulting
from repetitive shaking process whereas thermal fatigue resulting from repetitive
thermal changes during dipping and frying process. By applying finite element
method (FEM) using ANSYS Mechanical software, simulations for both scenarios
have been conducted to study the fatigue behavior of weld components on moulding
frame structure. At the end of this study, the results show that the thermal fatigue is
the main factor to the failure that occurs on the weld components. The maximum
stress that occurs on the moulding frame structure due to vibration is 12.6 MPa. The
stress magnitude is too low to induce fatigue damage since it far below the fatigue
endurance limit of materials applied. The results for thermal fatigue analysis show
that the moulding frame with 4 weld joints is the most critical in the whole moulding
frame structure. The minimum fatigue life for this model is 21 cycles of dipping and
frying process. Furthermore, the graphical approach of fatigue life prediction at any
stress value has been achieved by plotting the stress-life (S-N) results for all moulding
frame models. An experimental study will be required to support the reliability of the
results obtained from the simulation since a few parameters that naturally occur on
experimental approach such as welding flaws cannot be included in simulation.