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The chassis dynamometer (CHDY) is widely used as a system that can reproduce real road driving conditions indoors and evaluate the driving performance of completed vehicles. In this document, we evaluated the pitching motion of the vehicle during rapid acceleration and sudden stops using a vehicle restraint device that allows vertical and rotational motion near the center of gravity, a roller surface treated with high-friction material, and CHDY with different electric inertia control responses. In the analysis of the vehicle's pitching motion, we analyzed the behavior of the vehicle body and the engine behavior inside the vehicle through multi-point non-simultaneous measurement modal analysis. In the driving condition, we report on the low-frequency vibrations of the vehicle caused by rapid operation of the accelerator pedal, comparing the results from real road driving conditions and CHDY experiments. [Contents] ■ Preface ■ Analysis of vehicle pitching motion during rapid acceleration and sudden stops ■ Analysis of low-frequency vibrations of the vehicle due to accelerator pedal operation ■ Summary *For more details, please refer to the PDF document or feel free to contact us.

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Structural Change Prediction (SDM) refers to the process of converting the structural change matrix on a physical coordinate system into modal coordinates using the mode shape matrix. This is then added to the original modal parameters, and eigenvalue analysis is performed in the modal coordinates to obtain new modal parameters. This document clarifies the points to consider for practically applying SDM to automobiles using two case studies. Please take a moment to read it. 【Contents】 ■ Preface ■ Case Study of Passenger Car White Body ■ Case Study of Pickup Truck ■ Discussion ■ Conclusion *For more details, please refer to the PDF document or feel free to contact us.

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This document reports on cases of OMA (Operational Modal Analysis) using multi-point simultaneous measurements on SUV test vehicles, followed by cases of OMA and EMA (Experimental Modal Analysis) using multi-point non-simultaneous measurements on convertible car test vehicles. As a practical modal analysis for automobiles using a relatively small-scale system, OMA proposes a method to determine natural frequencies and damping ratios using SSI (Stochastic Subspace Identification), and to obtain mode shapes using ODS (Operational Deflection Shape). Additionally, EMA proposes a combination of sinusoidal excitation using a small electromagnetic shaker and the least squares complex frequency method. 【Contents】 ■ Preface ■ OMA (Operational Modal Analysis) ■ EMA (Experimental Modal Analysis) ■ Discussion ■ Conclusion *For more details, please refer to the PDF document or feel free to contact us.

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The theory of curve fitting in experimental modal analysis has a long history during which various methods have been developed, and it is even said that there are no further mathematical advancements to be made. In this document, we introduce a real-valued modal curve fitting method that advances the assumption of real modes by using only the imaginary part of the FRF (or the real part when the FRF is in terms of velocity/force). Additionally, we applied this method to the white body of a passenger car and a pickup truck, and we present a comparative analysis of the results obtained from the real mode method and the complex mode method. We invite you to read it. [Contents] ■ Preface ■ Real Mode Method ■ Case Study of Passenger Car White Body ■ Case Study of Pickup Truck ■ Conclusion *For more details, please refer to the PDF document or feel free to contact us.

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"ModalVIEW Plus/R2" is a high-performance, low-cost experimental modal analysis software. Depending on the application and purpose, it expands the options for data input channels and can be provided as an integrated system by combining impact hammers and accelerometers, such as those used in PCBs. Additionally, it can be used for analysis software and post-processing by importing Time/Frequency data from your existing FFT analyzers or data recording devices. 【Features】 ■ Equipped with dedicated screens for impact excitation/shaker excitation ■ Shape definition and DOF settings considering local coordinates ■ Automatic mode/manual mode extraction selection from stabilization diagrams ■ Validation function for modal parameters using MAC/synthesis ■ Achieves accurate modal analysis from data collection in a short time *For more details, please refer to the PDF materials or feel free to contact us.

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We would like to introduce a case study by F-MA Consulting, a specialist in vibration noise analysis technology, titled "Scuttle Shake Analysis of Open Cars Using OMA (Operational Modal Analysis)." The definition of scuttle shake is: "a phenomenon commonly seen in open cars with low body rigidity," "which manifests as a 'shaking sensation' when driving in urban areas at speeds of 40 to 60 km/h," and "is generally said to be caused by low-frequency (10 to 20 Hz) twisting modes of the body." 【Experimental Analysis Using ModalVIEW】 - Collection of acceleration and deceleration data from actual vehicle runs at each measurement point - Pole extraction using SSI from time history data - Calculation of mode shapes at each point from the extracted modes - Display of vibration modes in the operational state For more details, please contact us or download the catalog.

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