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PROJECT1 (Spring 2016
)
MECH 5390/6390/6396 Fundamentals of the Finite
Element Method
Due Date:
April 5, 2016
(Professor Lall)
INSTRUCTIONS
1. Write a report with the result of the problems below.
2. Submit your report as a WORD (.doc) file via CANVAS.
3. Turnin a hardcopy of your report in class.
4. Screen captures indicated in the questions below are a minimum requirement.
Document your model results with screen captures where necessary.
QUESTION‐1: DESIGN OF STABILITY‐BOOM
A retractable stabilityboom called the “outrigger”, is attached to the back of a heavylift truck and
is designed to provide stability for lifting heavy offcentered loads. Figure 1 shows the stabilityboom attached to the back of a truck in its retracted position. Figure 2 shows the stability boom
fully extended and engaged for an offcenter lift.
Figure 1: Retractable StabilityBoom attached to back of a Truck.
(Courtesy of Miller Industries)
Figure 2: Retractable StabilityBoom in FullyExtended and Engaged Configuration. (Courtesy
of Miller Industries)
Given that the stabilityboom is a 3stage telescopic arm as shown in Figure 2, made of structural
A36 steel with the Elastic Modulus, E = 200 GPa, Poisson’s Ratio, = 0.33, and yield strength,
ys = 250 MPa. Assume that the 2largest telescopic stages are rectangulartubular in xsection
and the final stage is a rectangular tube with closed end (Figure 2).
The stability boom is 1meter long in its retracted position and 2meter long in the fully extended
configuration. Assume that each of the 3telescopic stages have equal exposed lengths in the fully
extended configuration.
The truck is designed for a load capacity of 35,675 kg on the freetip of the stability boom.
Determine the xsection dimensions of the stability boom using the following steps:
(a) Develop a ConceptualModel for the fullyextended configuration of the stabilityboom.
Identify any assumptions, constraints, and boundary conditions. Justify why they are
reasonable, and why the conceptualmodel of the physical structure will represent the
structure accurately.
(b) Based on the ConceptualModel in Part (a), develop a FiniteElement Model of the stability
boom using (i) BEAM Elements (ii) Solid Elements. Initially assume the crosssection
dimensions. Show screenshots of your meshedmodel with dimensions, boundary
conditions, and loads.
(c) Determine the required section dimensions for the stabilityboom iteratively starting from
your initial guess in Part (b), using both the BEAM model and the Solid Model? Assume
a FactorofSafety of 2 at maximum load. Show all the cases analyzed. Clearly list any
sectionproperties used.
(d) Determine the freeend deflection at maximum load? Show the deformed and undeformed
configuration of the stabilityboom.
(e) Show the contour plot of the vonmises stress, and the longitudinal normalstress along the
length. Identify the location of maximum stress in the stability boom?
(f) Using your finite element model, show if a higher load capacity can be attained using an
alternate crosssection of the stability boom? Show all the sections analyzed.
QUESTION‐2
Determine the (a) deflections at points D and F and (b) axial stresses and forces in the structural
members using two methods:
(a) Using ANSYS Modeling and PostProcessing. Provide justification for the choice of the
element used in the analysis.
(b) Using handcalculations using the stiffness matrix of the BAR element.
(c) Evaluate the correlation between the FE results and the hand calculations.
(d) Explain any differences between the FE model and the hand calculations.