A reduced passive constrained layer damping finite element model based on the modified improved reduced system method

2017 ◽  
Vol 21 (2) ◽  
pp. 758-783
Author(s):  
Wei Li ◽  
Yansong He ◽  
Zhongming Xu ◽  
Zhifei Zhang

This paper proposed a new reduced passive constrained layer damping finite element model. The passive constrained layer damping structure is a sort of sandwich plate made up of a viscoelastic core sandwiched between two elastic faces. The model is built by combining the first shear deformation theory with the Golla-Hughes-McTavish model that takes the frequency dependence of the viscoelastic material property into consideration. Due to the Golla-Hughes-McTavish model, the stiffness, damping and mass matrices are at least doubled, which requires a large amount of calculation. Then, a modified improved reduced system method is proposed to reduce the order of the model. Finally, the proposed reduced model is compared to the Guyan reduction, the mode truncation and the improved reduced system models by two numerical examples. It demonstrates that the proposed modified improved reduced system method is obviously superior to the other three classical methods and the presented passive constrained layer damping model with the Golla-Hughes-McTavish model is an effective and accurate sandwich model, which can be applied to the finite element software.

Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Abdelhak Khechai ◽  
Aicha Bessaim ◽  
Mohammed-Sid-Ahmed Houari ◽  
Aman Garg ◽  
...  

In this paper, the bending behavior of functionally graded single-layered, symmetric and non-symmetric sandwich beams is investigated according to a new higher order shear deformation theory. Based on this theory, a novel parabolic shear deformation function is developed and applied to investigate the bending response of sandwich beams with homogeneous hardcore and softcore. The present theory provides an accurate parabolic distribution of transverse shear stress across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the functionally graded sandwich beam without using any shear correction factors. The governing equations derived herein are solved by employing the finite element method using a two-node beam element, developed for this purpose. The material properties of functionally graded sandwich beams are graded through the thickness according to the power-law distribution. The predictive capability of the proposed finite element model is demonstrated through illustrative examples. Four types of beam support, i.e. simply-simply, clamped-free, clamped–clamped, and clamped-simply, are used to study how the beam deflection and both axial and transverse shear stresses are affected by the variation of volume fraction index and beam length-to-height ratio. Results of the numerical analysis have been reported and compared with those available in the open literature to evaluate the accuracy and robustness of the proposed finite element model. The comparisons with other higher order shear deformation theories verify that the proposed beam element is accurate, presents fast rate of convergence to the reference results and it is also valid for both thin and thick functionally graded sandwich beams. Further, some new results are reported in the current study, which will serve as a benchmark for future research.


2021 ◽  
Vol 264 ◽  
pp. 113712 ◽  
Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Mohammed-Sid-Ahmed Houari ◽  
Ahmed Amine Daikh ◽  
Aman Garg ◽  
Tarek Merzouki ◽  
...  

2002 ◽  
Vol 8 (6) ◽  
pp. 877-902 ◽  
Author(s):  
W. Laplante ◽  
T. Chen ◽  
A. Baz ◽  
W. Sheilds

Vibration and sound radiation from fluid-loaded cylindrical shells are controlled using patches of Active Constrained Layer Damping (ACLD). The performance and the enhanced damping characteristics via reduced vibrations and sound radiation in the surrounding fluid is demonstrated both theoretically and experimentally. A prime motivation for this work is the potential wide applications in submarines and torpedoes where acoustic stealth is critical to the effectiveness of missions. A finite element model is also developed to predict the vibration and the acoustic radiation in the surrounding fluid of the ACLD-treated cylinders. The developed model is used to study the effectiveness of the control and placement strategies of the ACLD in controlling the fluid-structure interactions. A water tank is constructed that incorporates test cylinders treated with two ACLD patches placed for targeting specific vibration modes. Using this arrangement, the effectiveness of different control strategies is studied when the submerged cylinders are subjected to internal excitation, and the radiated sound pressure level in the water is observed. Comparisons are made between the experimental results and the theoretical predictions to validate the finite element model.


2020 ◽  
Vol 10 (15) ◽  
pp. 5102
Author(s):  
Carlos Valencia Murillo ◽  
Miguel Gutierrez Rivera ◽  
Junuthula N. Reddy

In this paper, a seven-parameter spectral/hp finite element model to obtain natural frequencies in shell type structures is presented. This model accounts for constant and variable thickness of shell structures. The finite element model is based on a Higher-order Shear Deformation Theory, and the equations of motion are obtained by means of Hamilton’s principle. Analysis is performed for isotropic linear elastic shells. A validation of the formulation is made by comparing the present results with those reported in the literature and with simulations in the commercial code ANSYS. Finally, results for shell like structures with variable thickness are presented, and their behavior for different ratios r/h and L/r is studied.


2012 ◽  
Vol 443-444 ◽  
pp. 751-756
Author(s):  
Li Jun Suo ◽  
Xia Guang Hu

In China, it is fact that porous concrete base has been used in the construction of asphalt pavement in recent years because porous concrete base has good performance. However, Reasonable design method has not been put forward so far. Therefore, it is necessary to analyze load stress and thermal stress of asphalt pavement which includes porous concrete base in order to put forward theoretical basis for pavement design method. In the paper, three–dimension finite element model of asphalt pavement, which includes porous concrete base and asphalt surface, is created for the purpose of studying load stress and thermal stress of porous concrete base in asphalt pavement. Based on numerical method of three–dimension finite element model, finite element software, such as ANSYS, is employed to study load stress and thermal stress of porous concrete base in asphalt pavement. After that, the effect of different factors on stress is studied, and the factors include thickness of surface, thickness of base and ratio of base’s modulus to foundation’s modulus. Finally, calculation results for stress are compared with each other, and it shows that load stress of porous concrete base decreases with increase of base’s thickness, while thermal stress of porous concrete base increases with increase of base’s thickness. Load stress and thermal stress of porous concrete base decrease with increase of surface’s thickness. Load stress and thermal stress of porous concrete base increase with increase of ratio of base’s modulus to foundation’s modulus.


2012 ◽  
Vol 479-481 ◽  
pp. 457-461
Author(s):  
Dong Hui Chen ◽  
Xin Lu ◽  
Xing Wang Chai ◽  
Bao Gang Wang ◽  
Hong Xia Guo ◽  
...  

In this paper,soil parameters and the collected data were tested and processed, and the changing trends of force with drilling depth were obtained and the maximum force applying to the working components was picked up. Compared with the smooth working component, the force applying to the unsmooth working components is smaller. Some parameters needed in Drucker-Prager soil model were measured and modified according to the basic tests. The simulation model was built in the finite element software -ANSYS. The simulation result is consistent with the actual testing result, which confirms the finite element model is correct .


1998 ◽  
Vol 120 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Guan-Liang Qian ◽  
Suong V. Hoa ◽  
Xinran Xiao

In this paper, a higher order rectangular plate bending element based on a Higher Order Shear Deformation Theory (HSDT) is developed. The element has 4 nodes and 20 degrees of freedom. The transverse displacement is interpolated by using an optimized interpolation function while the additional rotation degrees of freedom are approximated by linear Lagrange interpolation. The consistent element mass matrix is used. A damped element is introduced to the finite element model. The proposed FEM is used to calculate eigenfrequencies and modal damping of composite plates with various boundary conditions and different thicknesses. The results show that the present FEM gives excellent results when compared to other methods and experiment results, and is efficient and reliable for both thick and thin plates. The proposed finite element model does not lock in the thin plate situation and does not contain any spurious vibration mode, and converges rapidly. It will provide a good basis for the inverse analysis of vibration of a structure.


2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
R. M. Kanasogi ◽  
M. C. Ray

This paper deals with the analysis of active constrained layer damping (ACLD) of smart skew laminated composite plates. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs). A finite element model has been developed for accomplishing the task of the active constrained layer damping of skew laminated symmetric and antisymmetric cross-ply and antisymmetric angle-ply composite plates integrated with the patches of such ACLD treatment. Both in-plane and out-of-plane actuations by the constraining layer of the ACLD treatment have been utilized for deriving the finite element model. The analysis revealed that the vertical actuation dominates over the in-plane actuation. Particular emphasis has been placed on investigating the performance of the patches when the orientation angle of the piezoelectric fibers of the constraining layer is varied in the two mutually orthogonal vertical planes. Also, the effects of varying the skew angle of the substrate laminated composite plates and different boundary conditions on the performance of the patches have been studied. The analysis reveals that the vertically and the obliquely reinforced 1–3 PZC materials should be used for achieving the best control authority of ACLD treatment, as the boundary conditions of the smart skew laminated composite plates are simply supported and clamped-clamped, respectively.


2010 ◽  
Vol 456 ◽  
pp. 103-114
Author(s):  
Shi Ling Xing ◽  
Jian Shu Ye ◽  
Hang Sun

In order to use finite element software to complete the design or calculation of bridge multi-pile foundation, this paper discusses the finite element model (FEM) of a bridge multi-pile based on the theory and provisions in Code for Design of Ground Base and Foundation of Highway Bridges and Culverts (CDGBFHBC 2007) of china. For the FEM of a bridge-multi pile foundation, cap is regarded as a rigid body, piles are taken as beams, and boundary constraints are a series of horizontal springs and vertical springs. First, the formula of stiffness for horizontal springs and bottom vertical spring is derived according to elastic ground base theory and winkler hypotheses. Secondly, for the friction pile, the stiffness of vertical springs on piles side is derived basis of the principle of friction generated and simplified distribution of pile shaft resistance. Then, the FEM of multi-pile needs pay attention to three issues: the simulation of connections between piles and cap, elastic modulus needs discount, and the weight for pile underneath the ground line (or local scour line) needs calculate by half. Taking pile section bending moment often control the design and calculation of pile into account, this paper gives a simplified FEM of pile. Finally, an example is used to introduce the application of the FEM of bridge multi-pile foundation.


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