New Ultra-compact Spider-20H, Spider-20HE, & Spider-20i with 256 kHz Sampling Rate

Featuring the highest sampling rate provided in the industry at 256 kHz. Handheld battery powered system with wired & wireless network options and 20V input range. Sync between multiple devices. Choose the convenient portable model or industrial model for permanent mounting.

The Spider-20H, Spider-20HE, and Spider-20i received a hardware upgrade to support an impressive 256 kHz samping rate on all 4 input channels. It is the highest sampling rate offered in the market of compact analyzers. The high sampling rate is especially beneficial for measuring high orders and transient capture in blast tests, pyroshock events, drop shock tests, crash tests, etc.

In addition to the high samping rate, the input range is expanded to 20V to capture larger signals.

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.

Introducing Testing Plan in EDM Modal

With Modal Analysis software, all DOFs on the mesh of a structure under test needs be measured. The common practice is using the Input channel setting, with one incremental value to move on to the next batch of measurement points till all DOFs are measured.

Modal Testing & AnalysisJeff Zhao, Ph.D.June 25, 2020Structural Dynamics Testing

Modal Analysis of the Human Skull

Researchers at North Dakota State University have made great headway in understanding the behavior of the human skull under different strain rates. The study they carried out utilized a combination of computational and experimental modal analysis to compare the accuracy of different techniques used to model a human skull, and ultimately could increase the accuracy of dynamic simulations on the skull.

Comparison of Multi-Resolution Spectrum Technology and Regular FFT in Modal Analysis

Modal testing and analysis are crucial processes in the product development cycle. Sometimes the testing results are wrong by several magnitudes, especially in the low frequency bands where the frequency resolution is not sufficient. Crystal Instruments’ patented Multi-Resolution (MR) Spectrum technology helps overcome this issue with a unique solution.

Modal Analysis of Airplane Model Using EDM Modal

Analyzing the modal parameters of a structure is crucial in optimizing the mechanical properties of the test object. The natural frequencies, damping and mode shapes of the unit under test help in adjusting the design of the test structure which ultimately improves the structural behavior of the test unit.

Multi-Resolution Spectrum Analysis in Modal Testing

The latest 8.1 release of the Crystal Instrument’s EDM Modal software features multi-Resolution spectrum technology implemented into the MIMO FRF testing suite. Multiple passes of FFT yield a much finer resolution in the lower frequency region. This provides the advantage of a better estimation of the quality factor (or damping) and the amplitude of the frequency response functions at the resonant frequencies.

Simplify the User Interface and Manage Different Levels of Users

EDM’s Account Management program controls the accessibility of features from different users. This provides a structure for managing the privileges for different groups of users. The Account Manager can be used to prevent lower-level users from adjusting parameters or display settings. It also allows users to customize the toolbars for a simplified user interface. By hiding certain features, the UI can be made much easier to use.

Poly-X, the Poly-reference LSCF Implementation and Experiment

Abstract
A poly-reference least-square method for modal parameter identification of a system in frequency-domain is discussed and implemented. It can also be considered as a multi-reference frequency-domain implementation of the recognized time-domain based Least-Squares Complex Exponential (LSCE) estimator. The main advantages of the Poly-reference Least-Squares Complex Frequency-domain estimator (p-LSCF) are its capabilities of handling high system orders and high modal density. The stability diagram is much cleaner which makes the selection of system poles easier. Other advantages are lower computational times and the ability to handle multiple references. The Poly-X is Crystal Instruments’ version of p-LSCF, which is included in the EDM Modal software package. A MIMO FRF experimental test is carried out to demonstrate these advantages.

Vibration Visualization

The EDM Vibration Visualization feature is available in all modules of EDM software (VCS, DSA and Modal). This option provides fast and efficient structural model generation and full 3D visualization of the online vibration pattern on the structure under test

Modal Testing Using the CoCo-90X

Studying the modal properties of the structure under test is important to optimize the design of the test structure and to improve the NVH characteristics. Finite Element Analysis is widely used to obtain the mechanical properties of different objects. However, it is not only difficult to replicate the exact environmental constraints and boundary conditions but also challenging to obtain the damping ratios of the different modes. Experimental modal analysis not only helps in solving these issues but can also help in validating the results of the finite element model.

Hammer Impact Test Considerations

Roving excitation or response? Uni-ax or Tri-ax? SIMO or MIMO?

A modal impact hammer test is broadly classified between two types: roving hammer and roving response. Each method has its own pros and cons.