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Bicycle Frame Analysis of Structure
by
Patrick McAdams
Laboratory Section AA, Tuesday 2:30 p.m., January 16, 2007
Daniel Flores
Date of Laboratory: January 23, 2007
Report Submitted to: Jiangyu Li
EXECUTIVE SUMMARY
A structural analysis of a K2 bicycle frame was performed using three methods: analytical,
experimental, and numerical.
The analytical method was done using a truss analysis.
The
experimental was done through the application of 12 strain gages used to measure strain on
members of the bicycle frame under varying given applied loads.
From the values measured,
forces, stresses, and strains were calculated using material properties and geometry.
The
numerical method was done using finite element analysis in two ways: as a 2dimensional
structure and as a beam structure.
The analytical method proved to be too simple a model as it
only found axial stress, when we found there to be bending stress in our other two analyses.
The
errors for stress analysis were nearly 40% in one case.
Displacement was found experimentally
using a displacement gage, but it was determined that this value was too high as the linear trend
line had an exceptionally large yintercept.
Once this value was resolved, comparison to the
other methods found the analytical method to have an error around 50%, while the numerical
method had errors of roughly 26% and 4%.
It was found from these analyses that the front fork
would fail first by buckling under compression should the bicycle continue to be loaded with
more and more force.
The maximum force the fork could handle was determined to be around
119 kN.
It was concluded that in the future, strain rosettes should be used to ensure that the
strains were measured longitudinally along the members.
It was also suggested that further
analysis of bicycles be done on bicycles with varying materials, geometries, and loads to
examine how other factors may play a part in the stresses, strains, and displacements.
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View Full DocumentOBJECTIVES
Structural analysis is a very important aspect of mechanical engineering.
It allows for the
figuring out of failure and deformation in structures.
These structures come in all shapes and
sizes.
The analysis of structure can be done analytically, numerically, and experimentally.
This
lab will incorporate all three of these analysis methods to analyze a K2 bicycle.
The analytical approach will look at the bicycle as a truss structure, taking each member of the
bicycle to be members in a truss.
That is, each member is pinned at either end and assumed to
carry a shear force or bending moment.
This is assumed because each member of a bicycle is
slender and attached to another tube at the end.
This is not exactly a truss structure, but it will be
used to model the bicycle for stress and strain and will be a decent approximation of forces
within each member.
The experimental approach uses strain rosettes to measure the strains in members as many
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 Winter '07
 JiangyuLi
 Force, Truss, Bicycle, Bicycle frame, Bicycle fork, Top Tube

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