Vibration Testing Services

GEC (Gray’s) performs vibration testing services to help clients determine the resiliency of their components and assemblies. Vibration is the propagation of repetitive forces through an object disturbed from its equilibrium, which causes the particle or body to oscillate. Among the broad range of external forces that cause damage to objects every day, vibration presents a very active threat to the structural integrity of any piece in an assembly.
To illustrate, unaccounted-for vibrations undermined the stability of London’s Millennium Footbridge (now often referred to as the “Wobbly Bridge”) on its opening day. People walking on the bridge sent vibrations through the structure, causing it to oscillate from side to side. This unstable footing caused pedestrians to struggle for balance and sway in their own steps, a resonance that amplified the undulating of the bridge beneath them. The swaying grew so concerning that the government closed the bridge two days later for a redesign. Experts feared it could fail, much like the infamous Tacoma Narrows incident decades before.
Forces causing vibration in a structure can come from intended sources innate to the item’s purpose — such as recoil from firing a gun or rotating machinery — or from unintended sources incidental to its use — such as imbalance of an engine or shipping and transportation. These vibrations can have various detrimental effects resulting in fatigue failures, excessive noise, premature wear, loosening of fasteners, and so on. Because manufacturers and parts suppliers need to know early in the production process whether their components can withstand the forces expected to act on it, GEC provides them with vibration testing to validate their designs.

About Our Vibration Testing Methods

Our dynamic testing lab features five electrodynamic shaker tables. Our technicians use this advanced equipment to apply precise vibrations to samples and observe how they respond. We use three types of vibration testing:

  • Sinusoidal
  • Random
  • Sine-on-Random

Sinusoidal Vibration

This branch of vibration testing introduces uniform vibrations. Technicians carefully control these vibrations to ensure samples only experience a single, predetermined frequency at any time. This method proves useful for simulating environments where very steady vibrations are generated— such as those near equipment like a turbine wherein a sample will experience incessant vibrations at a given frequency.
Depending on the requirements of the test, GEC’s technicians may use a sine sweep technique to expose samples to a variety of frequencies and amplitudes back to back. Deliberately sweeping the sample with a range of excitation frequencies allows them to detect its resonant frequency. Because vibrations at this frequency cause systems to experience greater amplitudes than any other, subjecting a sample to extended periods under its resonant frequency can lead to accelerated fatigue damage. Purposefully doing so, using a technique called resonance search and dwell, gives our technicians insight into its resistance to failures caused by vibration.

Random Vibration

In contrast, random vibration introduces many excitations at the same time. True to its name, these vibrations consist of random frequencies and amplitudes within a predetermined frequency range. This method of testing more represents the “background noise” of vibrations that a component may face in service. Imagine people walking around the third floor of a busy hotel hosting a conference; while the presence of this large variety of vibrations may be anticipated, the specific frequency and strength of those vibrations cannot be predicted. The floor beneath them must hold up regardless.
GEC’s technicians use random vibration testing to more closely replicate everyday conditions, and many regulatory bodies require products and components to perform well in this testing before they are qualified for use.

Sine-on-Random Vibration

Finally, we also offer sine-on-random vibration testing. Our technicians employ this combination of the two methods when service conditions feature sinusoidal properties. By applying random background noise with featured sinusoidal peaks, they can simulate conditions like transportation — where random minor vibrations occur constantly as the transfer truck drives over the road, but a sinusoidal vibration propagates as they hit a pothole.
GEC’s technicians can set the frequency and intensity of sinusoidal vibrations independent from the random background vibrations. They can also decide whether to sweep frequencies and amplitudes with their sine vibrations or to keep them consistent.

The GEC Advantage

GEC’s dynamics lab also supports mixed environment testing to account for samples used in hot or cold service conditions. By combining vibration testing with our extensive thermal conditioning capabilities, we can more accurately predict failure modes exclusive to more severe service climates.
Furthermore, our lab maintains ISO 17025 accreditation through the A2LA to perform vibration testing services in accordance with a wide variety of internationally recognized standards — you can see the full list here.

Our combination of experience performing these methods, expansive capabilities, and accredited status makes GEC a perfect fit to provide for your vibration testing needs. Contact us today for a free quote!

Testing Capabilities

Dynamics Methods

  • Temperature Cycling
  • Temperature Shock
  • Combined Temp / Humidity
  • Combined Temp / Altitude
  • Combined Temp / Humidity / Altitude
  • High Temperature
  • Low Temperature
  • Resistance
  • Current
  • Insulation Resistance
  • Thermal Time Transient
  • Electrostatic Discharge
  • Dielectric Withstand Voltage
  • Magnetic Effects
  • Life Cycle (Charge / Discharge)
  • Continuity

Thermal Vacuum Methods

Environmental Conditioning Methods

  • Salt / SO2 Spray / Fog
  • Solar Radiation / Sunshine
  • Explosive Atmosphere
  • Explosive / Rapid Decompression
  • Rain
  • Freezing Rain
  • Fluid Susceptibility
  • Sand and Dust

Load Testing Methods

  • Tensile / Compression
  • Acceleration
  • Push
  • Drop
  • Impact
  • Random Drop / Tumble
  • Positive Pressure (Overpressure)
  • Temperature Cyclying
  • Temperature Shock
  • Combined Temp / Humidity
  • Combined Temp / Altitude
  • Combined Temp / Humidity / Altitude
  • High Temperature
  • Low Temeprature
  • Resistance
  • Current
  • Insulation Resistance
  • Thermal Time Transient
  • Electrostatic Discharge
  • Dielectric Withstand Voltage
  • Magnetic Effects
  • Life Cycle (Charge/Discharge)
  • Continuity
  • Salt / SO2 Spray / Fog
  • Solar Radiation / Sunshine
  • Explosive Atmosphere
  • Explosive / Rapid Dceompression
  • Rain
  • Freezing Rain
  • Fluid Susceptibility
  • Sand and Dust
  • Tensile / Compression
  • Acceleration
  • Push
  • Drop
  • Impact
  • Random Drop / Tumble
  • Positive Pressure (Overpressure)