US-based Sandia National Laboratories (Sandia Labs) has demonstrated a new and more environmentally friendly method to test a rocket part to ensure its avionics’ capability to survive the shock from stage separation during flight.

During the demonstration, the new method, known as Alternative Pyroshock Test, used a nitrogen-powered gas gun to shoot a 100lb steel projectile into a steel resonant beam.

The beam then transferred energy through a resonant cone attached to the rocket part being tested.

The energy transfer process imitates the conditions of stage separation in space.

Researchers used flight hardware to complete the first test of this kind, which was conducted this year.

Sandia Labs mechanical engineer Mark Pilcher said: “We recognised early in the programme that we need to seek out alternative test methods in order to reduce our hazardous work exposure, minimise environmental waste and develop a controlled and repeatable test capability.

“Investigating a large-scale non-explosive gas gun test became a reality when we partnered with Sandia’s large-scale mechanical test facilities.

“The combined team worked hard to get to this test.”

In addition, researchers at Sandia Labs employed Hopkinson bar technology to shoot a gas gun to test the rocket part.

"Investigating a large-scale non-explosive gas gun test became a reality when we partnered with Sandia’s large-scale mechanical test facilities."

Sandia Labs mechanical engineer Bo Song has used a Hopkinson bar measuring one inch in diameter to find alternative ways of rocket part testing involving the use of a gas gun.

During the research, Song and his team conducted small-scale testing with a metal rod nearly 20 times smaller than that used in the full-scale test.

The tests were conducted at Sandia’s Experimental Impact Mechanics Laboratory and found that Hopkinson bar technology could deliver the frequency levels and the mechanical energy required in the large-scale test to recreate conditions found during flight.

More than 50 such tests were conducted to find out the types of projectiles, how fast the gas gun required to shoot, how to design a Hopkinson bar-type apparatus called a resonant bar at a larger scale and various other aspects.

Image: Sandia National Laboratories representatives prepare a nitrogen-powered gas gun for the labs’ Alternative Pyroshock Test. Photo: courtesy of by Randy Montoya.