Post on 21-Jan-2017
Coffee Table MMAE 445 Design Project
Tricia Hale | Wojciech Lukaszczyk | Gerard Simon Prosper | Yash Surana | Alan Grossman
Initial IdeaCoffee tables have been around for a long time, and they have kept their basic
function of providing surface storage. However, internal storage is an issue.
The solution is to place a concealed compartment that would allow for surface
and internal storage with more convenience.
Initial ConceptConcept: A coffee table with a
middle section that rises to the
surface when pressed
Torsional spring and damper
system used to lift middle section
Middle section made to hold bottles
and glasses
Revised ConceptA spring damper system was too
complex for the time allotted.
A gas spring that can have a fixed
height seemed much easier.
The gas spring needed to have the
right amount of force to be
compressed, but also raise the
column.
Gas SpringsGas springs are easily
chosen by using the
configurator provided
by Bansbach.
The design was very
universal with the
addition of threads.
Engineering DrawingA drawing was made to create initial
dimensions, and was used to create a
3D model in Solidworks.
The dimensions were chosen to
represent a good height when sitting.
The center column would provide
support while concealing the lifting
mechanism.
Material SelectionAll long, thin surfaces are made from
high quality plywood.
Legs would be made from pine studs.
Anything that is not rectangular will be
made from aluminum.
Solidworks RenderingInitial renderings
provided a
aesthetically pleasing
coffee table.
It was time to create
an FEA model to see
if stresses were not
exceeding yielding.
1st Attempt at FEAOur initial simulation
contained errors in
that the applied loads
and boundary
conditions were not
accurate.
2nd Attempt at FEAWe got closer to what was
needed by applying the correct
boundary conditions.
Our loading was still inaccurate.
A point load used instead of a
distributed load over a certain
area.
2nd Attempt at FEAThis Von Mises stress shows a
maximum stress of 10MPa
The yield strength for this
material was 31 MPa
The Von Mises stress of 10 MPa
was far lower than the 31 MPa
yield stress.
An area of 4 inches by 12 inches
was created to represent
someone’s feet. The 350 lbs
was distributed evenly across
this area.
A much more accurate
representation of potential
stress was created.
3rd Attempt at FEA
The newly obtained Von Mises
stress was 8.2 MPa which was
far lower than the yield stress
of 31 MPa
This shows that our design can
handle the load safely
3rd Attempt at FEA
Solidwords model analyzed in Abaqus CAEUsing distributed instead of the
concentrated force, we
obtained a deflection 1.2mm
According to experience, this is
similar to what was expected.
Solidworks design of center column A center column was created
to bring up the various items
contained within the table.
The top would be the cutout
of the top surface.
The squares on top represent
the area that the hands would
cover when pushing the
center down.
Center Column Stress AnalysisVon Mises stresses show that
our stress was about 75.7
ksi.
The yield stress was at about
87ksi for the center rod.
Center Column DeflectionThe deflection came out to only
be 0.4 inches at the lowest
extreme.
The one handed push seemed
to work well and the two
handed push analysis was
deemed unnecessary.
Assembly AnimationThe table appears to be a regular coffee table until the center extends
upwards, revealing a storage compartment.
Special thanks to Tricia’s
boyfriend for sharing his
SOLIDWORKS wisdom.