What is mechanical shock testing?
In physics, when a force moves an object, it gains mechanical energy. Mechanical shock testing assesses how well a product or design can endure different forces and identifies its limitations.
Before a product goes to market, engineers must fully understand its strength, flexibility, and durability. Mechanical shock testing plays a crucial role in this process, determining a system's ability to survive sudden impacts.
Manufacturers use mechanical shock testing to be able to anticipate how shock dynamics will affect their systems and to be able to design products to withstand impacts such as drops, hits, falls, explosions, or any other source of transient vibration.
Industries like defense and electronics rely heavily on these tests to ensure their products function properly after being exposed to shock events in real-world environments and to obtain the necessary certifications to bring their product to market.
Why is mechanical shock testing performed?
Not all products will be used in a sedentary state; in fact, many will be exposed to regular shocks and vibrations that have the potential to inflict damage or even render the product unusable.
After a crash, a car is likely to sustain both physical and mechanical damage. The engine might not restart, and even if it does, the speedometer may stop working. This kind of scenario illustrates the potential effects of mechanical shock, and why it's necessary for manufacturers to understand shock and how to protect against it through testing.
Shocks can occur under various circumstances, including:
- Routine shipping and handling
- Accidental damage
- Regular use in cars and planes
- Explosive events in warfare
- Special cases like use of explosive bolts and pyrotechnics
Shocks are intense and unexpected, often causing significant damage despite engineers' precautions. Unplanned shocks can be even more devastating.
Effects of mechanical shocks include:
- Blunt force fractures
- Instability from cumulative damage
- Decreased reliability
- Invalidated scientific results
- Detonation of explosive elements
- Weakened or separated connections
- Bending of ductile items
- Mechanical failure from recurring shocks
- Shortened service life
What are the methods of mechanical shock testing?
Various methods of mechanical shock tests are conducted to make sure equipment stays functional under sudden forces or abrupt motion changes which have a tendency to degrade performance or cause permanent damage.
Unlike impact testing, mechanical shock tests specify the pulse’s shape, duration, and amplitude. These tests include pyrotechnic shock, drop shock, and free-fall shock.
Shock testing on mechanical shock machines
A mechanical shock machine shakes a table holding a device under test (DUT) with a sudden pulse of defined shape, duration, and intensity. Adjustments to the pulse are made by varying the machine's speed or impact force on the DUT.
Examples of mechanical shock machines include:
- Drop-shock machines
- Lightweight shock machines
- Medium-weight shock machines
- Hopkinson bar
Shock testing on shakers
A shaker is a quick and economical choice for standard shock tests as it is capable of creating various pulse shapes. However, unlike other shock machines that stop the table mechanically, shakers can only generate a set amount of speed and movement. To account for this limitation, the shaker controller uses a process called compensation.
Complex shock testing
Mechanical shock tests provide a straightforward way to evaluate product durability, but some products and scenarios call for more complex testing. Specialized software like Shock Response Spectrum (SRS) can recreate intricate shock pulses, mimicking real-world conditions. This software can generate synthetic pulses that closely match operational environments or replicate recorded signals using an iterative shock control loop.
Nemko’s mechanical shock testing services
Mechanical shock often leads to nonstructural failures in both mechanical and electrical systems.
Our expert-led testing program supports manufacturers by conducting rigorous mechanical shock testing to ensure products can withstand sudden impacts without sustaining damage while identifying where a product’s limitations lie.
The result is a consistent, high-quality product that meet industry standards and regulatory requirements, saving you time and money and giving you an edge over the competition.
Contact Nemko today to explore how our mechanical shock testing can enhance your product's design process.
