Type of Document Master's Thesis Author Francis, Justin David Author's Email Address email@example.com URN etd-05062002-100056 Title Welding Simulations of Aluminum Alloy Joints by Finite Element Analysis Degree Master of Science Department Aerospace and Ocean Engineering Advisory Committee
Advisor Name Title Johnson, Eric R. Committee Chair Gürdal, Zafer Committee Member Kapania, Rabesh K. Committee Member Stoumbos, Thomas Committee Member Keywords
- weld simulation
- finite element analysis
Date of Defense 2001-07-20 Availability unrestricted Abstract(ABSTRACT)
Simulations of the welding process for butt and tee joints using finite element analyses are
presented. The base metal is aluminum alloy 2519-T87 and the filler material is alloy 2319. The
simulations are performed with the commercial software SYSWELD+Â®, which includes moving
heat sources, material deposit, metallurgy of binary aluminum, temperature dependent material
properties, metal plasticity and elasticity, transient heat transfer and mechanical analyses. One-way
thermo-mechanical coupling is assumed, which means that the thermal analysis is completed first,
followed by a separate mechanical analysis based on the thermal history.
The residual stress state from a three-dimensional analysis of the butt joint is compared to
previously published results. For the quasi-steady state analysis the maximum residual longitudinal
normal stress was within 3.6% of published data, and for a fully transient analysis this maximum
stress was within 13% of the published result. The tee section requires two weld passes, and both a
fully three-dimensional (3-D) and a 3-D to 2-D solid-shell finite elements model were employed.
Using the quasi-steady state procedure for the tee, the maximum residual stresses were found to be
90-100% of the room-temperature yield strength. However, the longitudinal normal stress in the first
weld bead was compressive, while the stress component was tensile in the second weld bead. To
investigate this effect a fully transient analysis of the tee joint was attempted, but the excessive
computer times prevented a resolution of the longitudinal residual stress discrepancy found in the
quasi-steady state analysis. To reduce computer times for the tee, a model containing both solid and
shell elements was attempted. Unfortunately, the mechanical analysis did not converge, which
appears to be due to the transition elements used in this coupled solid-shell model.
Welding simulations to predict residual stress states require three-dimensional analysis in the
vicinity of the joint and these analyses are computationally intensive and difficult. Although the
state of the art in welding simulations using finite elements has advanced, it does not appear at this
time that such simulations are effective for parametric studies, much less to include in an
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