Posts in Vibration Test Control
Fatigue Damage Spectrum

The Fatigue Damage Spectrum (FDS) serves as a pivotal tool in the assessment of structural integrity, portraying the relationship between damage and natural frequency across the frequency domain. Its utility extends to testing laboratories, empowering them to craft precise Random vibration test profiles by analyzing acceleration vibration data derived from real-world environments. By using the FDS, these labs can accurately delineate the damage experienced by structures under dynamic loads, facilitating the development of robust testing protocols essential for ensuring product reliability and safety.

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Multi-Shaker Push-Push Vibration Test

Multiple shaker systems are typically used for vibration testing when the unit under test (UUT) is too long or too heavy to test with a single shaker. This approach overcomes the limitations of high drive requirements with a single shaker test. Multiple shaker systems also allow the UUT to be tested in various configurations and directions in the horizontal and vertical orientations.

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Mode Shape Characterization

Shaker applications involve the use of many attachments to the shaker’s armature. Head expanders, fixtures, adapters, and devices under test (DUT’s), all attach to the shaker for the testing process. While it is common to simply consider the added mass of these components, their deformation during vibration can also have a significant impact on the vibrations experienced at any certain point of interest.

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Test Group feature in EDM Vibration Control Software

This article discusses a new EDM 11.0 release feature called Test Group, which organizes multiple tests into sections, to run in sequence, and shares test configurations. EDM allows users to configure and re-use the same test for the same or different objects. All configurations and test parameters are applied to a single test. Settings can be loaded and applied to a new test from a saved library. Test configurations are easily shared by sharing just the test file.

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MESA Sine on Random Vibration Control

This paper concentrates on the MESA Sine on Random control per MIL STD 810H, method 514.8, annex D, 2.3 category 14. This category governs Sine on Random control for helicopters.

Crystal Instruments designed and released the Spider-80M Multiple-Exciter Single-Axis (MESA) vibration controller in 2018. Further details regarding the MESA testing system are available on the Sentek Dynamics website. Detailed product specifications may be requested from the Crystal Instruments team.

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Dual Excitation Shaker Push-push Testing

Dual excitation shaker systems are commonly used to test long or heavy devices under test (DUT). When the device under test is very long or too heavy, a single shaker cannot perform the test because of oversized dimensions or a large driving force. Thus a dual excitation shaker system is arranged as the solution. Users can fix the longer sized or heavy DUT horizontally or vertically on top of a dual excitation shaker system. Common arrangements are horizontal push-push, push-pull, and vertical.

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Understanding the Frequency Signature of a Head Expander

Head expanders are commonly used for vertical environmental testing. The purpose of the head expander is to extend the surface area of the shaker top to accommodate units under test (UUTs) with large dimensions for mounting and testing. One of the key parameters is the working frequency range associated with each head expander. The upper frequency is often used instead of the first resonance frequency of the head expander in vibration control tests.

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Earthquake Testing on a Three-Axis Shaker System

Earthquake testing is a crucial process that is used to determine the seismic performance of a structure. The utilization of a physical testing method helps users better understand the complexity involved in earthquake forces. A shaker table is typically used to execute a physical method of testing. The results from earthquake testing are used to optimize the design and material properties of the unit under test.

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Spiders with 256 kHz Sampling Rate

Crystal Instruments EDM 9.0 release introduces new additions to the Spider product line featuring support for sampling rates up to 256 kHz.

The new Spider-80Hi and Spider-80Ci are scalable versions of the Spider system featuring the impressive new 256 kHz sampling rate. Recording can also be performed at sampling rates up to 256 kHz for all input channels, up to 512 channels per Spider system.

The compact, ultra-portable four channel version of the Spider has also been developed to support a 256 kHz sampling rate. Currently, three variations of the compact Spiders supporting the 256 kHz sampling rate are available: Spider-20H, Spider-20HE, Spider-20i.

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ISTA 6-Amazon.com Performance Testing with Crystal Instruments Environmental Testing Solutions

The International Safe Transit Association (ISTA) partnered with Amazon.com to develop the 6-Amazon.com testing series to challenge the capability of packages and products to withstand transportation standards while utilizing the general simulation of actual transport hazards. Please note that these tests may not comply with carrier packaging regulations and are designed only to address transportation hazards.

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