Vibration testing is essential to determining the ability of a product to withstand the conditions it might experience during its lifetime. The testing simulates that conditions that occur in operations and transit and stretches across many industries. This testing assists in finding potential issues before they arise.
Without shaker testing, car seats would squeak with every change in the road surface. Airplanes would require significant repair after every flight. Consumer electronics would have shorter lifespans. Vibration testing is essential to maximizing the use and life of nearly every product.
Overview of Vibration Types:
There are two primary types of vibration testing. Random vibrations are vibrations that involve multiple frequencies at once. Sine vibrations are conducted one frequency at a time. From those two basic types, there are a number of specific tests including the following:
Random Vibration Testing – A random vibration test provides all frequencies simultaneously. This is considered to simulate real world movement and is the more realistic of the two primary types of vibrations. Random vibration tests can simulate vibration caused by different events such as operation, transportation and seismic.
Products can have multiple resonant frequencies. Random testing applies multiple frequencies at the same time. This process can expedite the analysis of the product providing valuable product life information in a short period of time. This saves significant time and money by reducing the need for repairs, maintenance and recalls.
Sine Vibration Testing – This test sweeps across a frequency spectrum. This determines and identifies any test article resonant frequencies. Sine sweeps are also called sinusoidal sweeps. Sine sweeps can identify the frequencies that generate the largest responses.
During product validation, a sine test can be used to maintain the shaker on the product’s resonance frequency. This is referred to as a Sine Dwell Vibration Test. This will essentially fatigue the product and either expedite a failure or show proof of the product’s ability to survive.
As a regulatory compliance test lab, we use sine sweeps to validate our shakers and fixtures. Shakers can develop issues such as cracked armatures and loose connections. Fixtures can have resonance frequencies as well. A fixture should never have a resonance in the frequency range of the test plan.
In addition to just Random and Sine, there are also combination vibration profiles that can be used. These are called Mixed-Mode Vibration Tests.
One example of a mixed-mode test is Sine on Random Vibration Testing. These tests provide further insight on the ability of a product to survive. The testing combines the underlying energy of a random vibration test with the resonance dwells of the sine test. The sine component of these mixed-mode tests can either be sweeping or fixed for the device under test.
An excellent example of a mixed-mode event is a helicopter. The helicopter incurs random vibration during flight. Add a missile launch or gunfire to it and an intense sinusoidal vibration is introduced. This combination of vibration events can impact operations of the aircraft and its components.
Mixed-mode testing such as sinusoidal on random is not required for all products. Specific testing requirements are often determined by a product’s industry.
Industries Requiring Vibration Testing
Aerospace Vibration Testing
In aerospace, the launch environment can be nearly two minutes of extreme vibration, pressure and acceleration. The load placed on systems and components can reach close to 20 g’s. Reentry, landing and recovery can be treacherous as well. Testing a product’s ability to withstand these events is mandatory to the success of the component and possibly the mission.
In aerospace testing, RTCA-DO-160 is one of the most common test standards used. For military aerospace testing the most common test standards are MIL-STD 202 and MIL-STD 810. There are also several commercial aerospace test standards as well.
Automotive Vibration Testing
Automobiles do not typically experience the same extreme terrains as a military vehicle, but some roads are pretty bad. Road vibrations are best simulated through the use of random vibration profiles. These profiles simulate normal road conditions, potholes, ramps, speed bumps and braking. Even the closing of a door, hood or trunk creates a vibration.
One of the challenges of automobile testing is noise. No one wants to hear a rattle in their car, so the industry developed squeak and rattle vibration testing. This shaker testing identifies components that require adjustments to maintain low decibels and our sanity while operating the vehicle. Of all of the component parts in a car, the seats undergo some of the most intense squeak and rattle testing.
Aviation Vibration Testing
Similar to aerospace, aviation products must be able to survive extremely harsh environments. The takeoff and landing of a plane generates vibration throughout the aircraft. Turbulence can also cause vibrations.
It is crucial that systems not be impacted by vibrations. Unwanted wing movements and other shock pulses can be catastrophic. Even a momentary loss of controls, communication or navigation can be devastating.
Consumer Products Vibration Testing
The every-day events or home and office life can create vibration stress on products. For many units, to achieve product certification like a CE Mark, vibration testing must be completed.
Every consumer product is subject to vibration during transportation to your home or office. As a certified package testing lab, we can provide all of the package testing needed to certify products and their packaging. We are an ISTA certified test lab and Amazon test facility. We also provide ASTM testing.
Military Vibration Testing
Vibrations can be equally detrimental in the air, on the water and on the ground. As previously covered, the operations of these units creates vibrations throughout the units. There are also mechanical vibrations prevalent during operations. Add in additional events such as gunfire, missile launches, torpedo launches and the presence of intense sine resonances can appear.
There are several military vibration standards with the most common being MIL-STD-810. Part One of this standard calls for testing at a vibration frequency of 25 HZ and above. This standard also covers the impacts of multiple events that can occur at the same time. These include temperature, humidity and altitude in combination with vibration.
Selecting the right shock and vibration testing facility to work with is important. Keystone Compliance is a unique vibration test lab because of our focus on the customer experience. From quote to report, our process is exactly what our customers need.
- Quotes are completed in a timely manner and our pricing is always very competitive.
- We are an ISO 17025 accredited testing laboratory.
- We assist with fixture design.
- We have significant vibration test equipment including five shaker tables. Our electrodynamic shakers allow us to accommodate short lead times on scheduling. Our shakers range in size and capability.
- Our vibration controllers and vibration test systems offer many capabilities. These include tracked resonance dwell and automated response limiting to any profile. We also provide classical and SRS shock testing.
- If failures do occur, we work with our customers to identify root causes and potential solutions.
Vibration testing is just one of the dynamics test services we offer. In addition to this, we also offer EMC testing and product safety testing. Contact Keystone Compliance to receive short lead times on schedules, thorough reports and unprecedented guidance. We offer the best vibration testing lab experience in the industry.