An experimental nonlinear low dynamic stiffness device for shock isolation

2015 ◽  
Vol 347 ◽  
pp. 1-13 ◽  
Author(s):  
Diego Francisco Ledezma-Ramirez ◽  
Neil S. Ferguson ◽  
Michael J. Brennan ◽  
Bin Tang
Keyword(s):  
Dynamic Stiffness ◽  
Shock Isolation

scholarly journals Shock Characteristics of the Opposed Disc Springs (ODS) Shock Isolator with Pretightening under Boundary Friction Condition

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
An-Min Hui ◽  
Ming Yan ◽  
Lei Zhang ◽  
Ying-Li Jin ◽  
Kaiping Wang ◽  
...  
Keyword(s):  
Dynamic Stiffness ◽  
Relative Displacement ◽  
Friction Condition ◽  
Boundary Friction ◽  
Shock Acceleration ◽  
Displacement Ratio ◽  
Stiffness Properties ◽  
Shock Isolation ◽  
Reasonable Description ◽  
Supporting Force

In this study, to solve the problems of shock environment and shock isolation, about which there is still a lack of reasonable description, an isokinetic shock distinguishing method (ISDM), which can quantitatively distinguish between shock and forced vibration state, is presented. And the shock isolation performance of an opposed disc springs (ODS) shock isolator with pretightening under boundary friction condition is investigated. The static and dynamic stiffness properties of the ODS shock isolator are discussed. Relying on ISDM, a shock dynamic model of the ODS shock isolator with pretightening under boundary friction condition is established. The average method is adopted to solve the model theoretically. The shock acceleration ratio (SAR), shock displacement ratio (SDR), and relative displacement ratio (RDR) of the model are calculated using the numerical method and verified by experiments. Both numerical and experimental results show that ISDM is effective. And the effects on isolation efficiency of the number of disc springs, additional supporting force, pretightening force, load, and the shock velocity constant of the ODS shock isolator are discussed, which provide guidelines for its further practical application.

Repeatability vs. multiple-trait models to evaluate shell dynamic stiffness for layer chickens

2017 ◽  
Vol 95 (1) ◽  
pp. 9 ◽  
Author(s):  
A. Wolc ◽  
J. Arango ◽  
P. Settar ◽  
N. P. O’Sullivan ◽  
J. C. M. Dekkers
Keyword(s):  
Dynamic Stiffness ◽  
Multiple Trait ◽  
Layer Chickens

Guaranteeing Anticipating Control in a Shock Isolation Problem

2018 ◽  
Vol 481 (4) ◽  
pp. 381-385
Author(s):  
N. Bolotnik ◽  
◽  
V. Korneev ◽  
Keyword(s):  
Shock Isolation

Exact solution by dynamic stiffness method for the natural vibration of porous functionally graded plate considering neutral surface

2021 ◽  
pp. 146442072098817
Author(s):  
Md. Imran Ali ◽  
Mohammad Sikandar Azam
Keyword(s):  
Power Law ◽  
Functionally Graded Material ◽  
Stiffness Matrix ◽  
Natural Vibration ◽  
Dynamic Stiffness ◽  
Functionally Graded ◽  
Neutral Surface ◽  
Functionally Graded Plate ◽  
Dynamic Stiffness Matrix ◽  
Graded Material

This paper presents the formulation of dynamic stiffness matrix for the natural vibration analysis of porous power-law functionally graded Levy-type plate. In the process of formulating the dynamic stiffness matrix, Kirchhoff-Love plate theory in tandem with the notion of neutral surface has been taken on board. The developed dynamic stiffness matrix, a transcendental function of frequency, has been solved through the Wittrick–Williams algorithm. Hamilton’s principle is used to obtain the equation of motion and associated natural boundary conditions of porous power-law functionally graded plate. The variation across the thickness of the functionally graded plate’s material properties follows the power-law function. During the fabrication process, the microvoids and pores develop in functionally graded material plates. Three types of porosity distributions are considered in this article: even, uneven, and logarithmic. The eigenvalues computed by the dynamic stiffness matrix using Wittrick–Williams algorithm for isotropic, power-law functionally graded, and porous power-law functionally graded plate are juxtaposed with previously referred results, and good agreement is found. The significance of various parameters of plate vis-à-vis aspect ratio ( L/b), boundary conditions, volume fraction index ( p), porosity parameter ( e), and porosity distribution on the eigenvalues of the porous power-law functionally graded plate is examined. The effect of material density ratio and Young’s modulus ratio on the natural vibration of porous power-law functionally graded plate is also explained in this article. The results also prove that the method provided in the present work is highly accurate and computationally efficient and could be confidently used as a reference for further study of porous functionally graded material plate.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

2021 ◽  
pp. 107754632110005
Author(s):  
Yonglei Zhang ◽  
Guo Wei ◽  
Hao Wen ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stiffness Characteristic ◽  
Negative Stiffness Mechanism ◽  
Isolation Systems ◽  
Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

Concrete Strength and Deformation Property under Sea Water Erosion Environment

2012 ◽  
Vol 446-449 ◽  
pp. 2554-2559 ◽  
Author(s):  
Jian Jun Cai ◽  
Feng Zhang ◽  
Wei Cui ◽  
Shou Shan Chen ◽  
Pu Lun Liu
Keyword(s):  
Large Scale ◽  
Failure Modes ◽  
Deformation Property ◽  
Sea Water ◽  
Dynamic Stiffness ◽  
Concrete Strength ◽  
Strain Curve ◽  
Water Erosion ◽  
Strength And Deformation ◽  
Erosion Environment

In order to effectively assess the concrete strength and deformation property under sea water erosion environment, concrete stress and strain curve was researched with the number of wet and dry cycle of 0 times, 10 times , 20 times, 30 times, 40 times, 50 times and 60 times based on the large-scale static and dynamic stiffness servo test set. The stress - strain curves of concrete was tested for the lateral pressure 10.8MPa, 14.4MPa, and 18.8MPa at different dry-wet cycles, The failure modes and superficial cracking characteristics of specimens are reported at different dry-wet cycles. Concrete elastic modulus and compressive strength were researched. Based on concrete mechanical theory , the classic Kufer-Gerstle strength criteria of concrete was used, a large number of test samples of multivariate data were nonlinear regressed, a biaxial concrete strength criterion was established taking into account the stress ratio and the number of dry-wet cycles.

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