SHAKER VIBRATION TESTING
Quality is the watchword of modern manufacturers and testing feedback is the way they achieve it. Vibration testing on electrodynamic or hydraulic vertical shakers (and on shaker-driven horizontal slip tables) is done for a broad range of reasons. These include demonstration of compliance with standards, new design qualification, stress screening, fatigue life evaluation, shock and earthquake survivability demonstration and various product pre-shipment audit and burn-in tests. Automotive, aerospace, avionic, telephonic, consumer electronic and military equipment providers use shakers to prove and sustain the quality of their wares. Shakers are used to subject a Device Under Test (DUT) to random, swept-sine and transient shocks.
A controller (more properly a Vibration Control System or VCS) is required to force the moving shaker table to impose the desired acceleration profile to the DUT. Crystal Instruments offers a broad range of VCS, offering more models than any other manufacturer. Our fourth-generation hardware is absolutely state-of-the-art; employing fast floating-point DSPs, our patent-protected dual-ADC input circuitry providing 150 dB dynamic range (simultaneously discerning ±600 nV in the presence of ±20 Volt) and robust IEEE 1588v2 Ethernet® communication providing less than 50 nS sample-time difference between system modules separated by hundreds of meters. This precision hardware is supported by a complete range of testing software to accomplish virtually any type of test your enterprise requires.
A complete testing system consists of a VCS, a shaker, a power amplifier to drive the shaker and an accelerometer mounted on the shaker’s vibrating table. The VCS is programmed with the desired PROFILE of the test (either an acceleration-versus-frequency spectrum or an acceleration-versus-time history). It provides a low-voltage DRIVE signal to the power amplifier which echoes a high power version of this signal to the shaker. The response motion of the shaker’s table is monitored by the accelerometer which returns the CONTROL signal to the VCS. Sophisticated real-time algorithms and circuitry within the VCS function to refine the DRIVE signal with time, forcing the CONTROL response to match the desired PROFILE. The VCS also performs a myriad of related functions including pre-test feasibility analysis (can this shaker/amplifier perform this test on this DUT and its mounting fixtures?), test-result report generation, and network communication.
Crystal Instruments’ sister company, Sentek Dynamics, provides permanent magnet and electrodynamic shakers, slip tables and power amplifiers. They offer air and water-cooled shakers with maximum force ratings from 20 N (4.5 lb) to 400 kN (88,000 lb) with strokes ranging from ± 4 mm (± 0.16 in) to ±100 mm (±3.9 in). Visit their website (www.sentekdynamics.com) for more detailed information.
Specifications & Standards Applicable to Crystal Instruments' Vibration Testing Systems
- ASTM D999-01 Standard Test Methods for Vibration Testing of Shipping Containers
- ASTM D3580 – 95 (2010) Standard Test Methods for Vibration (Vertical Linear Motion) Test of Products
- ASTM D4728 – 06 Standard Test Method for Random Vibration Testing of Shipping Containers
- BS EN 60721 Classification of Environmental Conditions
- BS EN 60068 General International Test Methods
- DEF STAN 00-35 UK Military
- ETS 300 Series European Telecommunications
- ISO 2247:2000 Packaging – Complete, filled transport packages and unit loads – Vibration tests at fixed low frequency
- ISO 8318:2000 Packaging – Complete, filled transport packages and unit loads -Sinusoidal vibration tests using a variable frequency
- ISO 9022-10:1998 Optics and optical instruments - Environmental test methods – Part 10: Combined sinusoidal vibration and dry heat or cold
- ISO 9022-15:1998 Optics and optical instruments – Environmental test methods – Part 15: Combined digitally controlled broad-band random vibration and dry heat or cold
Vibration Testing Capability
- Sine, Random, Classical Shock, Transient
- Time Wave Replication, Kurtosis Control
- Sine on Random, Random on Random
- Shock Response Spectrum Analysis & Synthesis
- Shock & Drop, Halt/Hass Application
- Complete Alarm, Limit & Notching Protection
Specifications & Standards Applicable to Crystal Instruments' Vibration Testing Systems (continued)
- ISO 9022-19:1994 Optics and optical instruments - Environmental test methods – Part 19: Temperature cycles combined with sinusoidal or random vibration
- IEC 60068-2-64 Environmental Testing Part 2: Test methods –Test Fh: Vibration, broadband random and guidance
- EIA-RS-186 Standard Test Methods for Passive Electronic. Component Parts. IEC Publication 68: Basic Environmental Test
- JIS C 0040:1999 Environmental testing Part 2: Tests -- Test Fc: Vibration (sinusoidal)
- MIL-STD-167 Department of Defense Test Method Standard – Mechanical Vibrations of Shipboard Equipment (Type I – Environmental and Type II – Internally-Excited)
- MIL-STD-202 Electronic and Electrical Component Parts
- MIL-STD-750 Test Methods for Semiconductor Devices
- MIL-STD-810 Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests
- NAVMAT P-9492 Navy Manufacturing Screening Program that provides guidance concerning the use of temperature cycling and random vibration as manufacturing screens for defects in both parts and workmanship.
- RTCA-DO-160 Section 8 Vibration
Free Article Download
- Download An Introduction to Vibration Testing Systems (courtesy of Sentek Dynamics).