impact testing systems

during my 2b term at waterloo, i completed an undergraduate research assistantship in the university's forming & crash lab. i designed two versions of a new piece of equipment for the lab; a pneumatic high-velocity, low energy impact sled, and a drop tower, both for testing lightweight materials and structures.

i first created a spreadsheet calculator to determine the impact energy and velocity for component sizing.

i designed the sled using solidworks. it was pneumatic, using the same infrastructure as the main impact sled in the lab. the pneumatic cylinder was sized according to the previous calculations, with low-friction inserts to allow the central piston to slide freely. the sled connection point was designed at the center of mass of the impactor to eliminate moment loads during impact.

i incorporated overload protection features (shear pin, impact attenuator) to minimize the risk of damage to peripheral equipment in case of accidental overload.

as i progressed, i was guided to pivot the project towards a drop tower system to better suit the lab's current priorities.

i brought my learnings from the sled design to begin the process of designing the drop tower, beginning with component sizing, drop height, impactor mass and springs, used for providing additional impact energy and speed.

i iterated several times on the main impactor body, and landed on a structure comprised of welded plates, with out-of-plane ribs for stiffness. the central cavity was designed to hold additional payload.

the lifting carriage was designed to hold the impactor body via electromagnets. additionally, a solenoid was used as a secondary latch and fail-safe.

to provide additional energy, optional springs were added at the top of the impactor stroke. these springs would pass through the lifting carriage and preload against the impactor.

finally, at the bottom of the tower, honeycomb impact attenuators were placed in case of overload. instrumentation was left empty as specific testing needs were not yet defined.

ultimately, both systems were shelved as the lab's main design engineer prioritized the project and designed a new system from scratch, but it was a great exercise in mechanical design from first-principles and holistic system design, including electrical aspects and pneumatics.