Transcript Progress_presentation-110509.ppt

A Designer’s Approach for
Optimizing an End-Loaded
Cantilever Beam while
Achieving Structural and
Manufacturing Requirements
Timothy M. Demers
November 5, 2009
Schedule
• A bit behind schedule
– First Progress Report posted 11/5 (3 weeks late)
– Second Progress Report will be posted NLT
11/13 (1 week late)
• Back on schedule
– Final Draft on 11/27
– Final Report on 12/11
Reason for Schedule Slip
Background
•
Optimization can be employed to find the best solution to problems that are quantifiable.
Determines optimum solution by calculating minimum or maximum value of a quantified
parameter by varying design variables under the given design constraints.
•
Structural optimization problems grouped into three categories:
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In many industries achieving an optimum design is beneficial and sometimes critical to
success.
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Sizing optimization typically applied to truss-type structure. Plate thickness and beam crosssectional areas are examples of the sizing design variables which can be modified.
Shape optimization determines the optimal boundaries of a structure for a defined fixed topology.
Spline control points are adjusted.
Topology optimization overcomes a deficiency because the optimum topology is independent of
the initial starting design. For this reason topology optimization methods are commonly utilized at
the conceptual stage of a design process.
Flight components - a lighter component and system can directly reduce launch costs and reduce
the number of missions required.
Optimization provides either the most efficient and effective use of the material in addition
to minimizing the weight of the entire structure.
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In the studies examined by Fazil Sonmez, the goal of optimization “was to minimize the weight of
the structure, in others to increase mechanical performance, e.g. to minimize stress concentration,
maximize fracture strength, buckling strength, fatigue life, and heat flux, minimize peak contact
stress, compliance, peak acceleration, and the probability of failure for brittle materials, and
optimize dynamic behavior of structures”
Optimization Methods
• Too many to list all
• Some are:
– Trial and error
– Most current techniques employ some form of
finite element analysis (FEA) software
– Newer codes utilize fully stressed design
• ESO
Methodology
• Based on evolutionary structural optimization
(ESO) method
– Begin with simple, rectangular, two-dimensional,
cantilever beam with end load of 1500 pounds
– Calculate beam thickness based on the highest stressed
section
– Generate beam using Dassault Systems CATIA V5®
– Analyze beam for baseline structural representation
using Comsol Multiphysics®
– Design and analyze ten different beam designs to
eliminate the ineffective material
– Compare and rank designs based on weight and strength
– Iterate successful designs to create even lighter designs
or to resolve minor structural inadequacies
– Compare and re-rank for final consideration