Answering that question is called design validation. There are a number of
methods for doing design validation. One is load testing. The design is built
and subjected to a load greater than the foreseen rated capacity by a large
safety factor. If the build survives the load, the design is validated.
Another is destructive testing. The design is built and subjected to
ever-increasing load until it fails. If the failure occurs after the design was
subjected to its maximum load + safety factor, the design is validated. A third
method is rules-of-thumb. Some designs are too large or too complex to be
subjected to load tests or destructive testing. The engineering establishment
has developed, over the years, rules on design and materials that, if followed
rigorously, will produce results whose behavior can be reliably predicted. A
design can be validated in some instances by demonstrating that the
rules-of-thumb have been rigorously followed.
The newest method of validation is through software simulation.
Finite Element Analysis, or FEA as it is known, takes a bill of materials, a 3-D
model and the rules of physics and engineering and allows simulations to be run.
Loads can be simulated and the results are presented visually and graphically.
Stress areas immediately become visible. Failure points and the manner of
failure also become visible. A design can then be simulated to its rated
capacity + safety factor and examined to see if it is strong enough.
Unusual, but plausible, loading scenarios can be run to determine how a design
will stand up to misuse and abuse. Simulations can be run that will
determine where failure will begin. Problem areas can then be noted in
inspection and maintenance instructions to ensure that preventative maintenance
is as effective as it can be.
This is a very powerful and useful capability. The
COSMOS
FEA package comes integrated with the Solidworks drawing software we use.
That allows us to take a preliminary design, attempt to validate it, and if it
will not meet requirements, change the design immediately until the design
requirements are met. That powerful capability ensures that we can get the
desired results from a design BEFORE fabrication begins--which can result in
huge cost savings.