Is it really necessary to reject a double impact?

Are they really a problem?

Let's talk about this.

I know that many people will say that a double impact is totally unacceptable. It is not the optimum condition for collecting impact data for a modal test. However, under certain circumstances, it may be reasonable to accept a measurement that has resulted from a double impact. Let's discuss this problem that may arise when a double impact occurs and explain how to determine if the measurement is acceptable or not.

NewsDr. Pete AvitabileJune 26, 2019Non-applications

Crystal Instruments Sponsors 2019 SAE Noise and Vibration Conference

The Society of Automotive Engineers (SAE) held the 2019 Noise and Vibration Conference in Grand Rapids Michigan this year. The conference, which is a biennial event, took place from June 10th to the 13th and drew roughly 1,000 engineers focused on NVH (Noise, Vibration and Harshness) and sound quality measurements. Crystal Instruments was proud to take part in sponsoring the conference this year.

NewsDarren Fraser - Vice President of SalesJune 25, 2019Non-applications

Now Offering: Crystal Instruments Rentals

Crystal Instruments is pleased to offer 15- or 30-day rental systems, providing users with an easy and accessible option to try one of our latest systems. Users can access the full power of Crystal Instruments’ Engineering Data Management (EDM) software along with a full featured hardware system.

Visit www.crystalinstruments.com/ci-rentals to learn more.

NewsCrystal InstrumentsJune 25, 2019Non-applications

Automatically Run Pre-Defined Vibration Tests Using Digital Inputs

Combined vibration testing is gaining prominence due to the advancement of test equipment technology driven by the need to accomplish simultaneous testing of multiple measurement quantities. Vibration testing combined with temperature, humidity or a combination of other quantities has enabled the creation of test environments closely resembling typical scenarios in which DUTs operate.

Vibration Test ControlSandeep MallelaJune 21, 2019Environmental Testing

Modal Space - In Our Own Little World

I ran one test with an x-excitation and can see some modes and another test with a y-excitation and see some different modes. Could I use an oblique angle instead?

Well, that's a very good question. Its one that comes up often in terms of running modal tests with a shaker excitation. Of course it is totally acceptable to run one test with a shaker at some oblique angle to the structure. But the only thing we need to be careful about is to assure that we don't select the reference point at the node of a mode.

NewsDr. Pete AvitabileMay 29, 2019Non-applications

2019 IEST ESTECH Conference & Exposition - Las Vegas, NV

The 2019 IEST ESTECH conference was held in Las Vegas, NV from April 29 through May 2nd, 2019. This year, Dr. James Zhuge provided a technical presentation explaining Crystal Instruments’ combined Temperature, Humidity, and Vibration (THV) Control system. Dr. Zhuge provided the opportunity for attendees to gain first-hand knowledge regarding Crystal Instruments latest technologies offered for environmental testing systems. The Crystal Instruments THV system provides one convenient user Interface to set up schedules for temperature, humidity, vibration, and more.

NewsAli Farrokhian - Western Region Sales ManagerMay 28, 2019Non-applications

2019 Automotive Testing Expo Europe in Stuttgart, Germany (May 21-May 23, 2019)

Crystal Instruments and Sentek Dynamics attended the 2019 Automotive Testing Expo held in Stuttgart, Germany. Every year all the main players in the automotive testing industry display their new products and technologies at this exhibition.

NewsJordi Gargallo - Europe Sales ManagerMay 25, 2019Non-applications

Running Multiple-Input Multiple-Output (MIMO) Vibration Control Tests Without a PC (Black Box Mode)

The capabilities of Crystal Instruments’ Spider devices are well known and the ability of the Spider to operate without a PC makes it advantageous for several applications, including vibration control.

View Statistics Time History Signals in Vibration Control Software

Crystal Instruments recently released version of EDM 8.0 software allows users to view the selected characteristics (e.g., Peak, RMS or Peak to Peak) of a channel versus time for the entire duration of the test. This feature is included in all vibration control tests and allows users to track user-defined characteristics of any channel (including the control signal) for the duration of a test.

MIMO FRF Testing of License Plate

Extracting the natural frequencies, damping shapes, and mode shapes of a structure aids in improving the design of the unit under test. In this case, the modal characteristics of a license plate is acquired by performing a modal analysis.

Modal Space - In Our Own Little World

Could you explain the difference between time domain, frequency domain and modal space? I hear it all the time but I'm not sure what's the difference.

There's a lot to explain but let's start with something simple.

NewsDr. Pete AvitabileApril 1, 2019Non-applications

Automotive NVH Seminar 2019 in Birmingham, UK - March 13th 2019

Crystal Instruments’ partner AcSoft provided a helpful Automotive NVH Seminar on March 13, 2019 at the National Conference Center in Birmingham, UK. AcSoft is a valued partner and distributor of Crystal Instruments data acquisition solutions in the United Kingdom.

NewsJordi Gargallo - Europe Sales ManagerMarch 26, 2019Non-applications

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.

Announcing Crystal Instruments’ new distributor, Avenir Technologies FZE for the United Arab Emirates, Saudi Arabia and Kuwait region

Crystal Instruments (CI) is excited to announce Avenir Technologies FZE as our new distributor in the United Arab Emirates region. Avenir Technologies FZE is located in the UAE, with offices in Dubai and Abu Dhabi.

NewsJordi Gargallo - Europe Sales ManagerMarch 18, 2019Non-applications

May 2019 Experimental Modal Measurement and Analysis Seminar (Montreal & Toronto, Canada)

Join Crystal Instruments’ “Experimental Modal Measurement and Analysis Seminar” from May 6-7, 2019, in Montreal, Canada and from May 9-10, 2019, in Toronto, Canada. All are invited to attend.

Registration cost is $199, visit the following link to register: http://www.Swiftpage6.com/dalimar.dalimar/SurveyMODALSEMINAR2019/Survey.aspx

NewsCrystal InstrumentsMarch 15, 2019Non-applications

Crystal Instruments Blog

Is it really necessary to reject a double impact?

Are they really a problem?

Let's talk about this.

I ran one test with an x-excitation and can see some modes and another test with a y-excitation and see some different modes. Could I use an oblique angle instead?

Could you explain the difference between time domain, frequency domain and modal space? I hear it all the time but I'm not sure what's the difference.