Optimized Design of Aluminum Cross Car Beam (CCB) Based in Modal Strain Energy Analysis

An aluminium cross car beam (CCB) for new energy is designed with CATIA. And then,modal analysis is taken by using simulation software-NASTRAN. As nature frequencies can't meet the design target, optimization is performed according to the modal strain energy contour. After structure is strengthen, the first vertical nature frequency of the aluminum CCB(mounted on trimmed car body,with closures and interiors) reaches 35.4Hz.While the first lateral nature frequency reaches 36.5 Hz. Besides,comparing to steel CCB,the weight of the aluminum CCB reduces by4.4 kilogram.

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Looseness localization for bolted joints using Bayesian operational modal analysis and modal strain energy

Advances in Mechanical Engineering ◽

10.1177/1687814018808698 ◽

2018 ◽

Vol 10 (11) ◽

pp. 168781401880869 ◽

Cited By ~ 3

Author(s):

Yu-Jia Hu ◽

Wei-Gong Guo ◽

Cheng Jiang ◽

Yun-Lai Zhou ◽

Weidong Zhu

Keyword(s):

Modal Analysis ◽

Strain Energy ◽

Damage Index ◽

Operational Modal Analysis ◽

Modal Identification ◽

Bolted Joints ◽

Mode Shapes ◽

Bolted Connections ◽

Modal Strain Energy ◽

Beam Structures

Bayesian operational modal analysis and modal strain energy are employed for determining the damage and looseness of bolted joints in beam structures under ambient excitation. With this ambient modal identification technique, mode shapes of a damaged beam structure with loosened bolted connections are obtained based on Bayesian theory. Then, the corresponding modal strain energy can be calculated based on the mode shapes. The modal strain energy of the structure with loosened bolted connections is compared with the theoretical one without bolted joints to define a damage index. This approach uses vibration-based nondestructive testing of locations and looseness of bolted joints in beam structures with different boundary conditions by first obtaining modal parameters from ambient vibration data. The damage index is then used to identify locations and looseness of bolted joints in beam structures with single or multiple bolted joints. Furthermore, the comparison between damage indexes due to different looseness levels of bolted connections demonstrates a qualitatively proportional relationship.

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Structural Health Monitoring Using Modal Strain Energy

Volume 2: 11th Biennial Conference on Reliability, Stress Analysis, and Failure Prevention; 7th International Conference on Design Theory and Methodology; JSME Symposium on Design and Production; Mechanical Design Education and History; Computer-Integrated Concurrent Design Conference ◽

10.1115/detc1995-0151 ◽

1995 ◽

Author(s):

Robert S. Ballinger ◽

David W. Herrin

Keyword(s):

Dynamic Response ◽

Modal Analysis ◽

Strain Energy ◽

Structural Integrity ◽

Dynamic Structure ◽

Experimental Modal Analysis ◽

Modal Strain Energy ◽

Various Boundary Conditions ◽

Structural Region ◽

High Strain Energy

Abstract This research combines analytical and experimental modal analysis techniques to verify the structural integrity or monitor the “health” of a dynamic structure. Central to the procedure is the development of a baseline dynamic fingerprint model of the structure. The dynamic fingerprint is verified with experimental modal analysis and correlation. After the structure is placed into service, damage can be determined by comparing the current dynamic response with the baseline dynamic fingerprint response. The unique aspect of this procedure is that the current dynamic response is enforced on the undamaged baseline dynamic fingerprint model. Should damage exist, the structure is forced to deform in an unnatural manner, and high strain energy results. Significant differences in the normalized modal or operating strain energy density identify structural regions where a loss of stiffness, weakening of the structure, and/or damage has occurred. This identification of a potentially “unhealthy” structural region allows a quick visual inspection of the region or further analytical and/or experimental submodelling of the area to precisely identify the damage. The method is ideally suited to CAE application. The method is demonstrated analytically and experimentally for two structures: an eight-bay cantilevered truss structure and a rectangular plate with various boundary conditions.

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Applying constrained layer damping to reduce vibration and noise from a steel-concrete composite bridge: An experimental and numerical investigation

Journal of Sandwich Structures & Materials ◽

10.1177/1099636218789606 ◽

2018 ◽

Vol 22 (6) ◽

pp. 1743-1769 ◽

Cited By ~ 2

Author(s):

Quanmin Liu ◽

Xiaozhen Li ◽

Xun Zhang ◽

Yunlai Zhou ◽

Y Frank Chen

Keyword(s):

Strain Energy ◽

Energy Analysis ◽

Constrained Layer Damping ◽

Statistical Energy Analysis ◽

Train Track ◽

Coupled Vibration ◽

Modal Strain Energy ◽

Composite Bridge ◽

Track Bridge ◽

Loss Factors

Structure-borne noise from railway bridges has become increasingly severe due to increased train speeds and axle loads. Constrained layer damping can suppress structural vibration and noise considerably across a wide frequency range by dissipating vibrational energy via damping layer shear deformation. This paper proposes a theoretical method of calculating the train-induced vibration and noise of a constrained layer damping-enhanced railway bridge based on the train–track–bridge coupled vibration, the modal strain energy method, and statistical energy analysis. First, the vibration responses of bridge decks were obtained via train–track–bridge coupled vibration calculations. Second, the constrained layer damping subsystem modal loss factors were determined via modal strain energy analysis and converted to damping loss factors in 1/3 octave band. Third, upon substituting the vibration energies of the decks and the damping loss factors of constrained layer damping subsystems into the statistical energy analysis power balance equations, the transmitted vibration energy results from various bridge subsystems were determined by solving the referenced equations. The structure-borne noise from the bridge was finally determined by analyzing the vibratory energies of all of the bridge subsystems using vibro-acoustic theory. Numerical analysis and field measurements of vibration and noise from a three-span steel–concrete composite bridge before and after constrained layer damping installation were performed. The predicted train-induced vibration and noise agreed well with the measured results. The stringer web and flange vibration velocity levels were reduced by 10.5 dB and 6.1 dB, respectively, and the sound pressure level at a measurement point 25 m (horizontal) from the track centerline and 1.5 m off the ground decreased by 4.3 dB(A).

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Fault Simulation and Online Diagnosis of Blade Damage of Large-Scale Wind Turbines

Energies ◽

10.3390/en12030522 ◽

2019 ◽

Vol 12 (3) ◽

pp. 522 ◽

Cited By ~ 4

Author(s):

Feng Gao ◽

Xiaojiang Wu ◽

Qiang Liu ◽

Juncheng Liu ◽

Xiyun Yang

Keyword(s):

Energy Spectrum ◽

Modal Analysis ◽

Large Scale ◽

Wavelet Packet ◽

Fault Simulation ◽

Simulation Software ◽

Operational Modal Analysis ◽

Energy Change ◽

Stable Operation ◽

Modal Strain Energy

Damaged wind turbine (WT) blades have an imbalanced load and abnormal vibration, which affects their safe and stable operation or even results in blade rupture. To solve this problem, this study proposes a new method to detect damage in WT blades using wavelet packet energy spectrum analysis and operational modal analysis. First, a wavelet packet transform is used to analyze the tip displacement of the blades to obtain the energy spectrum. The damage is detected preliminarily based on the energy change in different frequency bands. Subsequently, an operational modal analysis method is used to obtain the modal parameters of the blade sections and the damage is located based on the modal strain energy change ratio (MSECR). Finally, the professional WT simulation software GH (Garrad Hassan) Bladed is used to simulate the blade damage and the results are verified by developing an online fault diagnosis platform integrated with MATLAB. The results show that the proposed method is able to diagnose and locate the damage accurately and provide a basis for further research of online damage diagnosis for WT blades.

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Structural Damage Detection Based on Strain Energy and Evidence Theory

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.48-49.1122 ◽

2011 ◽

Vol 48-49 ◽

pp. 1122-1125 ◽

Cited By ~ 5

Author(s):

Hui Yong Guo ◽

Zheng Liang Li

Keyword(s):

Damage Detection ◽

Structural Damage ◽

Strain Energy ◽

Energy Equation ◽

Damage Identification ◽

Detection Method ◽

Evidence Theory ◽

Modal Strain Energy ◽

New Energy ◽

Damage Extent

In order to solve the damage detection problem, a damage detection method based on strain energy and evidence theory is presented in this paper. First, an evidence theory method is proposed to identify structural damage locations. Then, structural modal strain energy is utilized to quantify structural damage extents. In general, structural strain energy dissipation should be equal to the change of modal strain energy, according to this theory, a new energy equation is deduced, and structural damage extent can be obtained through the solution of the equation. The simulation results show that the method can perfectly identify damage locations and extents. Therefore, the proposed method is effective for the structural damage identification.

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