2. Project Statement
The purpose of this project is to build a prototype small wooden beam that
meets design requirements purposed by Flexible Beams, Inc. The assigned Design
Requirements for this Team are as follows:
X-axis Load of 400lb
Y-axis Load of 250lb
Beam Weight Restriction of 260 g
X-axis Deflection: min. = .06 in max. = .20 in
Y-axis Deflection: min. = .03 in max. = .20 in
Cost limit of $11.00
Teams will all be using the same exact resources and the wood being used is
Basswood which has an Elasticity of: 1.28x10^6 psi. For a successful design it must
deflect, weigh, cost within the given parameters, must have a cross-section that is
symmetrical to the centroidal axes. Also the object of this assignment is to build
your beam so that it holds the load and comes as close as possible to the desired
deflection while minimizing its weight
In creating the design it must reflect proper use of the engineering design process,
effective decision-making, good engineering judgment, engineering calculations to
support the design, and adequate and appropriate documentation.
3. RESEARCH
How are prototypes used in Design?
The object of prototyping, the building and testing of the design is to work out the
‘bugs’ before time and resources are spent on making the design look presentable.
In other words, make sure your “working model” works before you pretty it up.
(Design Process sheet)
What are alternatives to physical Prototypes?
Computer-generated prototypes.
Virtual-prototypes.com
CAD software
What is a safety factor?
The factor of safety also known as Safety Factor is used to provide a design margin
over the theoretical design capacity to allow for uncertainty in the design process.
Factor of safety is recommended by the conditions over which the designer has no
control, which is to account for the uncertainties involved in the design process.
Mechanical Engineering Blog, "Factors of Safety." Last modified April 5, 2013.Accessed June 10,
2013.http://www.mechanicalengineeringblog.com/tag/safety-factor/.
Load Types
There are three special load types that beams can be designed for, they include:
Dead loads (D) are those which of a concrete slab, or the weight of a wall. Those
loads are always present and do not change.
Live Loads (L) are typically occupancy type loads. You are a type of Live Load in the
structure you are in right now. American Society of Civil Engineers publishes
a book (ASCE 7) with guidance for the amount of live load that should be
used for different structures.
Roof Live Loads (Lr) are similar to Live Loads, but are specific to the roof and are
typically related to construction or maintenance activities.
Snow Loads (S) are exactly want they sound like, loads cause by snow. Local
building codes often dictate the appropriate ground or design snow loads to
use. These are typically basic loads. Drift and unbalanced conditions should
be accounted for as needed.
Other Loads are less common in beam design but can include Wind (W), Seimic or
Earthquake (E), Rain (R), Lateral Earth (H), etc.
4. Kujawa, Tom. WebStructual, "How to Design a steel Beam." Last modified 2010.
Accessed June 14, 2013. http://webstructural.com/how-to/steel-beam/.
