Dynamic Parameters Tuning Using Structural Dynamic Modification

Structural dynamic modification is a popular approach to obtain desire frequencies and dynamic characteristics. It has been observed that reanalyzing the modified structure usually involves complicated calculations when modifications are concerned with numerous degrees of freedom (DOFs), especially adding substructures to these DOFs. This paper proposed a method to reanalyze the frequency response functions (FRFs) of structures with multiple co-ordinates modifications. Two different cases are taken into consideration in the modifications, including adding (or decreasing) masses, stiffness, and damping, as well as adding spring-mass substructures, which makes the method more practical. This method is developed by employing Sherman–Morrison and Woodbury (SMW) formula based on the FRFs related to the modifications coordinates of the original system. The advantage of this method is that neither a physical model nor a modal model is required; instead, it needs only the FRFs, which can be directly measured by experimental modal testing. Another salient feature of this proposed strategy is that the FRFs of the modified structure can be calculated in only one step. Validation of this proposed method is demonstrated using various numerical examples. It is shown that the method is very effective and can be considered for real applications.

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Beam Element Structural Dynamics Modification Using Experimental Modal Rotational Data

Journal of Vibration and Acoustics ◽

10.1115/1.2874446 ◽

1995 ◽

Vol 117 (3A) ◽

pp. 265-271 ◽

Cited By ~ 3

Author(s):

John A. Cafeo ◽

Martin W. Trethewey ◽

H. Joseph Sommer

Keyword(s):

Finite Element ◽

Cantilever Beam ◽

Degrees Of Freedom ◽

Element Model ◽

Structural Dynamic ◽

Modal Data ◽

Structural Dynamic Modification ◽

Dynamic Modification ◽

Rotational Degrees Of Freedom ◽

Fixed Beam

Structural dynamic modification (SDM) of a fixed-free (cantilever) beam to convert it into a fixed-fixed beam with experimental modal data is presented. The SDM focuses on incorporating experimental rotational degrees-of-freedom (DOF) measured with a novel laser measurement technique. A cantilever beam is tested to develop the experimental modal database including rotational degrees of freedom. A modal database from a finite-element model also is developed for comparison. A structural dynamic modification, with both databases, is performed using a Bernoulli-Euler beam to ground the free end of the cantilever beam. The hardware is then modified and a second experimental modal analysis of the resulting fixed-fixed beam performed. A finite-element model of the fixed-fixed beam also was created. Comparison of results from these four tests are used to assess the effectiveness of SDM using experimental modal rotational data. The evaluation shows that provided high quality experimental rotational modal data can be acquired, SDM work with beam elements can be effective in yielding accurate results.

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A COMPARATIVE STUDY OF STRUCTURAL DYNAMIC MODIFICATION AND SENSITIVITY METHOD APPROXIMATION

Mechanical Systems and Signal Processing ◽

10.1006/mssp.2001.1451 ◽

2002 ◽

Vol 16 (4) ◽

pp. 585-597 ◽

Cited By ~ 12

Author(s):

KENG C. YAP ◽

DAVID C. ZIMMERMAN

Keyword(s):

Comparative Study ◽

Structural Dynamic ◽

Structural Dynamic Modification ◽

Dynamic Modification ◽

Sensitivity Method

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Structural Dynamic Modification Based on Combined Approximations Method

E3S Web of Conferences ◽

10.1051/e3sconf/202125203032 ◽

2021 ◽

Vol 252 ◽

pp. 03032

Author(s):

Yuchen Jin ◽

Xiaochen Yang ◽

Rui Feng ◽

Wenjie Zuo ◽

Guikai Guo

Keyword(s):

Sensitivity Analysis ◽

Taylor Series Expansion ◽

Least Square Method ◽

Least Square ◽

Structural Dynamic ◽

Dynamic Design ◽

Structural Dynamic Modification ◽

Dynamic Modification ◽

Combined Approximations Method ◽

Combined Approximations

Structural dynamic modification plays an important role in structural dynamic design. This paper presents an algorithm for dynamic modification of the structure, which is based on the Combined Approximations (CA) approach, sensitivity analysis, Taylor series expansion and the least square method. The feasibility of the algorithm is verified by a numerical example and the results show that the algorithm is accurate enough and easy to be implemented.

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Structure Dynamic Modification and Optimization for High-Speed Face Milling Cutter

Materials Science Forum ◽

10.4028/www.scientific.net/msf.471-472.663 ◽

2004 ◽

Vol 471-472 ◽

pp. 663-667 ◽

Cited By ~ 2

Author(s):

Wei Xiao Tang ◽

Xing Ai ◽

H.Y. Wu ◽

Song Zhang ◽

H. Jiang

Keyword(s):

High Speed ◽

Milling Process ◽

Face Milling ◽

Relative Speed ◽

Structural Dynamic ◽

High Speed Milling ◽

Structural Dynamic Modification ◽

The Face ◽

Dynamic Modification ◽

The Stability

Due to the complexity of high-speed milling process by high relative speed and interrupted cutting, the face milling cutters possess the multi-order modes and the vibrating displacements of the cutting edges under each modes affect adversely both the surface roughness and the life of machine/tool system worse than other structures. In order to improve the stability of milling process, this work focuses on the influence of the variables such as structure geometries and constraint conditions on the eigenfrequencies and modeshapes of cutter. As an example, the dynamic characteristics of several face cutters are analyzed and optimized by structural dynamic modification (SDM) techniques.

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