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Owing to the increasing demand of shock absorbing function,
the traditional bicycle frames are no longer suitable
for current bikes, and the design methodology of
bicycle frame also needs some revolution. Traditionally,
engineers analyze the prejudged structures time and again to
modify the previous design. However, the structure optimization
provides us more efficient design process and the proper
direction to revise the design. As the base of structure
optimization, the topology optimization is appropriate
for the structure design in the conceptual design phase. This
method combining finite element analysis and optimization
algorithm analyzes the structure and changes the design
variables continuously in the design iterations.
The mountain bike(MTB) consists of the front body, the rear
body, the fork, and the rear shock absorber. A five degree
of freedom model is established to simulate the dynamic
characteristic of MTB. This study defines the design domains,
loading cases, and boundary conditions for the front frameand
the rear frame, respectively, to obtain the static topology
optimization model. The shock absorbing effect and the frame
stiffness fo the new design ofMTB frame are considered
simultaneously. To satisfy the above demands, the study
integrates topology optimization and dynamic simulation as a
mechanism of dynamic analysis. In the mechanism, the positions
of the shock absorber arethe input data, and the accelerations
of the frame are the output. Using the accelerations as the
object to be minimized, the above mechanism is used to compute
the object function value, and the positions of shock absorber
is chosen as design variables. The road surface is assumed as
a sinuous wave. Thestudy utilizes simulated annealing(SA) method
to obtain the solution of above optimization problem, and posts
transient responses to compare the optimal design with the
initial design.
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