A constrained assumed modes method for solution of a new dynamic equation for an axially moving beam

Sharifnia, Mahdi; Akbarzadeh, Alireza

doi:10.1016/j.camwa.2016.08.018

Cited by 12 publications

(12 citation statements)

References 23 publications

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“…Compared with the constrained modal test, the free modal test is easier to realize without the coupling interference of other key components. Compared with the results of free modal analysis, the vibration characteristics obtained from the free modal test can verify the accuracy of the threshing cylinder model, and then the constraint modal analysis can be applied to the threshing cylinder according to the actual working state to replace the constraint modal test to avoid the dynamic coupling between the working parts, so that the vibration characteristics obtained from the solution are more accurate and reliable [34].…”

Section: Free Modal Testmentioning

confidence: 99%

Vibration Analysis and Parameter Optimization of the Longitudinal Axial Flow Threshing Cylinder

Wang

et al. 2021

Symmetry

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The longitudinal axial flow threshing cylinder of the full feeding rice combine harvester is widely used in China and works with violent vibration. To explore the source of the excitation affecting the vibration and to reduce the vibration, a finite element modal analysis and multipoint input and multipoint output (MIMO) modal test were performed to solve the natural vibration characteristics. By analyzing the excitation frequency, we concluded that the main reason for the resonance was the coupling between the rotation frequency of the threshing cylinder and the first natural frequency. To avoid the influence of resonance and realize a lightweight design, we proposed a combination of size optimization and topology optimization. The second rotation orthogonal combination test was designed to analyze the first natural frequency, maximum stress, and maximum deformation of the threshing cylinder, and the threshing cylinder was reconstructed as a central symmetrical structure to balance the rotational inertia force. The field experiment results showed that the amplitudes of the optimized threshing cylinder were significantly lower than those of the original threshing cylinder. This study provides ideas for solving the vibration characteristics of rotating parts and provides an important reference for the design of vibration reduction and weight reduction of key parts in the field of agricultural machinery.

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Section: Free Modal Testmentioning

confidence: 99%

Vibration Analysis and Parameter Optimization of the Longitudinal Axial Flow Threshing Cylinder

Wang

et al. 2021

Symmetry

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“…Beside the two most popular methods of GEF and ANCF, new researches with new ideas are also performed for different problems of beam large deflection; see [33][34][35][36][37][38][39]. Analytical methods such as assumed modes method [40][41][42][43][44] can also be developed or combined with the finite element method for use in the large deflection of the beam structures.…”

Section: And Mahdi Sharifniamentioning

confidence: 99%

A new beam element for analysis of planar large deflection

Sharifnia

2018

J Braz. Soc. Mech. Sci. Eng.

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In the present study, a simple and efficient finite element approach is presented for large deflection analysis of both the straight and curved Euler-Bernoulli beams in the planar static problems. The linear stress-strain relationship is assumed for the Euler-Bernoulli beam. In some of finite element methods, displacements together with rotations, and in some others, positions are considered as the main fields of interpolation. However, in the present study, the main idea for the interpolation is using the dimensions of the deformed element instead of the displacements. Therefore, the slope angle (like the previous works) and the length of beam centroidal axis (unlike the previous works) are used as the main field parameters. This treatment creates simplicity in the constitutive equations. Next, using the weighted residual method, the constitutive equations are applied to the element. Using the equilibrium equations and kinematic equations, the position coordinates of the nodes are related to the internal forces and the main field parameters. In the present study, three-node element and, consequently, Simpson's 1/3 rule is used for integration. For solving nonlinear equations of the beam, the Newton-Raphson method is used. Finally, several numerical examples are presented and compared with the previous works to illustrate the validity and efficiency of the new element.

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“…Two main computational methods are used in flexible multibody dynamics: assumed mode method (AMM) and finite element method (FEM). The AMM can still be extended for use in more complicated systems (Sharifnia and Akbarzadeh, 2014, 2016a, 2016b, 2016c, 2017). Some researchers compared the results of the AMM with experimental results (Ettefagh et al, 2018; Korayem et al, 2014, 2016; Luo, 1993; Nagaraj et al, 1997; Yim et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear dynamics of flexible links in planar parallel robots using a new beam element

Sharifnia

2020

Journal of Vibration and Control

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In the present research, a previously presented beam element in planar static problems is extended to planar dynamic problems. As investigated in the previous work of the author, formulation of the presented Euler–Bernoulli beam element is simpler and the beam element more efficient than similar elements in large deflection problems. In the present element, the main idea is estimating the dimensions of the body in the deformed configuration, instead of estimating its absolute or relative positions. Therefore, two parameters, the length and slope angle of the beam centroid curve, are selected to be estimated by interpolating polynomials. To verify the efficiency of the element, obtained results for the flexible pendulum are compared with previous works. Because of the simple and efficient formulation of the element, it can be efficiently used for dynamic analysis of planar flexible linkages, and especially in flexible parallel robots, which are the main aims of the present research. Finally, the inverse dynamic of the flexible 3-RRR parallel robot is presented.

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A constrained assumed modes method for solution of a new dynamic equation for an axially moving beam

Cited by 12 publications

References 23 publications

Vibration Analysis and Parameter Optimization of the Longitudinal Axial Flow Threshing Cylinder

Vibration Analysis and Parameter Optimization of the Longitudinal Axial Flow Threshing Cylinder

A new beam element for analysis of planar large deflection

Nonlinear dynamics of flexible links in planar parallel robots using a new beam element

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