Experimental Modal Analysis of Appropriate Boundary Conditions for the Evaluation of Cross-Laminated Timber Panels for an In-Line Approach

2021 ◽  
Vol 71 (2) ◽  
pp. 161-170
Author(s):  
Adam Faircloth ◽  
Loic Brancheriau ◽  
Hassan Karampour ◽  
Stephen So ◽  
Henri Bailleres ◽  
...  

Abstract Transverse modal analysis of timber panels is a proven effective alternative method for approximating a material's elastic constants. Specific testing configurations, such as boundary conditions (BC) and location of sensor and impact, play a critical role in the accuracy of the results obtained from the experimental assessment. This article investigates signal-specific details, such as the signal quality factor, that directly relate to the damping properties and internal friction as well as frequency shifting obtained from six different BCs. A freely supported (FFFF), opposing minor sides (shorter length) simply supported, and major sides (longest length) free (SFSF), as well as the reverse of the SFSF configuration with minor sides free and major lengths simply supported (FSFS) and all sides simply supported (SSSS) setup, are investigated. Variations into the proposed methods used to achieve an FFFF supported system are also considered. A combination of experimental testing in parallel with finite element analysis was conducted to re-create the setup that would be used within a manufacturing facility for nondestructive assessment of full-size cross-laminated timber panels. The differences between all BC configurations for their resonance frequency quality and location indicate that a freely supported system provides higher-resolution results, good comparison of less than 10 percent error with the finite element analysis and experimental results, and advantages in a simple experimental setup for the intended application.

1981 ◽  
Vol 103 (4) ◽  
pp. 385-391 ◽  
Author(s):  
B. S. Thompson

Variational theorems are presented for analyzing the vibrational response of flexible linkage mechanisms and the surrounding acoustic medium in which they are immersed. These theorems are established by generalizing Hamilton’s principle through using Lagrange multipliers to incorporate field equations and boundary conditions within the functional. The same philosophy is adopted to handle the conditions at the fluid-structural interface. When independent arbitrary variations of the system parameters are permitted, these acousto-elastodynamic theorems yield as characteristic equations the equation of motion for each member of the linkage, the acoustical wave equation, the compatibility conditions at the interface between the fluid and solid continua, and also the boundary conditions. These variational statements provide the foundations for several different classes of finite element analysis.


2015 ◽  
Vol 6 (6) ◽  
pp. 759-774
Author(s):  
André F. B. P. Pinto ◽  
S.M.O. Tavares ◽  
José M. A. César de Sá ◽  
P.M.S.T. de Castro

Purpose – The purpose of this paper is to use PAM-CRASH, a finite element analysis solver, to assess the performance of a mass production vehicle cross car beam (CCB) under an overlap frontal crash scenario (crashworthiness). Simulation results were reviewed according to what is plausible to register regarding some critical points displacements and, moreover, to identify its stress concentrations zones. Furthermore, it was also computed the CCB modal analysis (noise, vibration and harshness (NVH) assessment) in order to examine if its natural modes are within with the original equipment manufacturer (OEM) design targets. Design/methodology/approach – The available data at the beginning of the present study consisted of the structure CAD file and performance requirements stated by the OEM for NVH. No technical information was available concerning crashworthiness. Taking into account these limitations, it was decided to adapt the requirements for other mass production cars of the same category, as regards dynamic loading. A dynamic explicit code finite element analysis was performed throughout the CCB structure simulating the 120e−3 s crash event. For the modal analysis, there were some necessary modifications to the explicit finite element model in order to perform the analysis in implicit code. In addition, the car body in white stiffness was assigned at the boundaries. These stiffness values are withdrawn from the points where the CCB is attached to the car body’s sheet metal components. Findings – Although the unavailability of published results for this particular CCB model prevents a comparison of the present results, the trends and order of magnitude of the crash simulation results are within the expectations for this type of product. Concerning modal analysis, the steering column first natural frequency has a percent deviation from the design lower bound value of 5.09 percent when local body stiffness is considered and of 1.94 percent with fixed boundary conditions. The other requirement of the NVH assessment regarding a 5 Hz minimum interval between first vehicle CCB mode and the first mode of the steering column was indeed achieved with both boundary configurations. Originality/value – This study is a further confirmation of the interest of numerical modeling as a first step before actual experimental testing, saving time and money in an automotive industry that has seen an enormous increase of the demand for new car models in the last decade.


2011 ◽  
Vol 347-353 ◽  
pp. 1276-1280
Author(s):  
Hong Liang Hu ◽  
Rui Jie Wang ◽  
Chun Ling Meng ◽  
Guo Feng Li

Abstract. Combining characteristic of the Wind Tturbines's rotary support, using finite element method, the paper probe the rotary support finite element analysis of static and modal analysis. Through the static analysis of the rotary support, receiving the deformation and stress-strain results; through modal analysis,receiving the 6-order natural frequency and vibration shape.Analyzing of the main failure forms and Dynamic performance ,the results provide a theoretical basis of improvement of the design and to finalize the program.


Author(s):  
Y B Park ◽  
D Y Yang

In metal forming, there are problems with recurrent geometric characteristics without explicitly prescribed boundary conditions. In such problems, so-called recurrent boundary conditions must be introduced. In this paper, as a practical application of the proposed method, the precision cold forging of a helical gear (which is industrially useful and geometrically complicated) has been simulated by a three-dimensional rigid-plastic finite element method and compared with the experiment. The application of recurrent boundary conditions to helical gear forging analysis is proved to be effective and valid. The three-dimensional deformed pattern by the finite element analysis is shown, and the forging load is compared with the experimental load. The profiles of the free surface of the workpiece show good agreement between the computation and the experiment.


2012 ◽  
Vol 229-231 ◽  
pp. 919-922
Author(s):  
Bao Dong Bai ◽  
Guo Hui Yang ◽  
Bing Yin Qu ◽  
Jian Zhang

In this paper, the modal analysis was carried out on the core and cavity of a 160KVA dry-type transformer based on the finite element analysis software of ANSYS. And the simulation results of the natural frequencies and modal shapes were obtained, which provided a theoretical guidance to the design of the transformer structure, and were meaningful to reduce the vibration and noise level of the transformer.


2013 ◽  
Vol 677 ◽  
pp. 273-277
Author(s):  
Xiao Xin Gong ◽  
Qiang Lu

In order to analyze vibration characteristics of whole structure of the spherical grinder, the finite element analysis software is applied to finite element modal analysis of the structure. 3D model of spherical grinder is established by Pro/ENGINEER software. Finite element model of spherical grinder is established in the finite element analysis software ANSYS Workbench. The previous 6-order inherent frequencies and the corresponding vibration modes are obtained through the finite element calculation. According to the vibration intensity distribution, the corresponding improvement measure is put forward. It provides theoretical basis for dynamic analysis and improved design of spherical grinder.


10.29007/815q ◽  
2018 ◽  
Author(s):  
Shubhangi Umale ◽  
Dr.Sangeeta Shinde

In the present work, Finite element analysis is done by using FEM based software ANSYS (version 15) on simply supported rectangular plate with uniformly distributed loading condition. The results obtained for two different material properties of steel and aluminium are compared by using static structural and modal analysis.The analysis result of deformation, stress and frequency at each mode on simply supported rectangular plate obtained by ANSYS are compared for two material properties. And these results are compared with regression analysis for accuracy.


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