scholarly journals EXPERIMENTAL ANALYSIS OF STRUCTURAL DAMPING FOR BOLTED AND WELDED SPLICE CONNECTION JOINT FOR IPE-80 STEEL PROFILE

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Ognjen Mijatović ◽  
Zoran Mišković ◽  
Ratko Salatić ◽  
Rastislav Mandić ◽  
Valentina Golubović-Bugarski ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Experimental Analysis ◽  
Damping Capacity ◽  
Dynamic Problems ◽  
Structural Damping ◽  
Structural Joints

Progress and demands of all types of constructions imposed the need for the development of modernstructures that are lightweight, but at the same time have high damping capacity and stiffness. Theconsequences of these requirements are increased dynamic problems related to vibrations anddissipative processes in structure connection joints. Structural joints are the main reason for thesignificant reduction of the level of energy dissipation and source of structural damping so thereforethey have become a subject of interest to many researchers. The aim of this paper is to present someproblems regarding research of structural damping and the importance of study Contact Mechanicsto better understand the problem of structural damping.

FINITE ELEMENT MODELING OF DAMPING CAPACITY IN NANO-CRYSTALLINE MATERIALS

2010 ◽  
Vol 01 (03) ◽  
pp. 421-433 ◽  
Author(s):  
M. YADOLLAHPOUR ◽  
S. ZIAEI-RAD ◽  
F. KARIMZADEH
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Grain Boundary ◽  
Composite Model ◽  
Grain Structure ◽  
External Loading ◽  
Damping Capacity ◽  
Crystalline Materials ◽  
Nano Crystalline ◽  
Local Plastic Strain

Plastic deformation of materials is a major source of energy dissipation during external loading. In nano-crystalline (NC) materials, local plastic strain may arise even if the overall external load is below the yield stress of the material because of the grain structure. In this paper, the damping capacity of nano-crystalline materials is modeled by considering the grain structure. First, the grains are modeled by using a composite model. The composite model takes each oriented crystal and its immediate boundary to form a pair. Next, the finite element method in conjunction with the composite model is employed to evaluate the energy dissipation of nano-crystalline material under cyclic loading. The influence of the grain size and the external loading on the energy dissipation is investigated numerically. Energy dissipation in each of the two parts (i.e. grain and grain boundary) is also calculated as an attempt to understand the effect of grain boundary on energy dissipation.

Experimental Analysis of Damping and Tribological Characteristics of Nano-CuO Particle Mixed Lubricant in Ball Bearings

2015 ◽  
Vol 14 (03) ◽  
pp. 1450026
Author(s):  
E. Prakash ◽  
K. Sivakumar
Keyword(s):  
Experimental Analysis ◽  
Nano Particles ◽  
Tribological Characteristics ◽  
Precipitation Method ◽  
Damping Capacity ◽  
Ball Bearings ◽  
Test Results ◽  
Nano Fluid ◽  
Ball Surface ◽  
Film Lubrication

Experimental analysis of damping capacity and tribological characteristics of nano CuO added Servosystem 68 lubricant is attempted. CuO nano particles were synthesized by aqueous precipitation method and characterized. Prior to dispersion into lubricant, CuO nano particles were coated with 0.2 wt.% surfactant (Span-80) to stabilize the nano fluid. Tribological characteristics of particle added lubricant were tested in ASTM D 4172 four ball wear tester. Scanning electron microscopy test results of worn surfaces of nano CuO particle added lubricant were smoother than base lubricant. The particle added lubricant was applied in a new ball bearing and three defected ball bearings. When particle added lubricant was used, the ball defected bearing's vibration amplitude was reduced by 21.94% whereas it was 16.46% for new bearing and was ≤ 11% for other defected bearings. The formation of protection film of CuO over ball surface and regime of full film lubrication near the ball zone were observed to be reason for improved damping of vibrations.

scholarly journals Experimental Analysis on the Cyclic Response of Beam to Column Joints: State-of-the-Art at Salerno University

2014 ◽  
Vol 8 (1) ◽  
pp. 227-247 ◽  
Author(s):  
M. Latour ◽  
G. Rizzano
Keyword(s):  
Energy Dissipation ◽  
Design Process ◽  
Research Group ◽  
Experimental Analysis ◽  
State Of The Art ◽  
Initial Stiffness ◽  
Design Rules ◽  
Cyclic Behaviour ◽  
Analytical Work ◽  
The University

Aiming to provide a contribution to the codification of design rules for dissipative joints to be applied to MRFs, in last five years, a comprehensive experimental and analytical work dealing with the cyclic behaviour of beam-to-column joints has been developed by the research group of the University of Salerno. In particular, the activity has regarded the study of both classical and innovative typologies characterized by the same initial stiffness and resistance but by different hysteretic behaviours due to the different source of energy dissipation supply imposed in the design process. In this paper, the main results of such a study, performed at the laboratory of materials and structures of the University of Salerno, are reported in order to provide an overview on the main mechanisms involved in the energy dissipation of partial-strength connections. A particular attention is given to the design issues by presenting the procedures aimed at providing to the joints adequate characteristics in terms of stiffness, resistance and ductility supply by hierarchically controlling the behaviour of the single joint components. Furthermore, the results of tested joints (classical and innovative) are compared in terms of hysteretic behaviour and energy dissipation supply in order to point out the advantages of the different connecting systems.

Exploratory Study of Energy Dissipation at Aircraft Structural Joints

1962 ◽  
Vol 34 (5) ◽  
pp. 729-730
Author(s):  
Eric E. Ungar ◽  
Creighton M. Gogos
Keyword(s):  
Energy Dissipation ◽  
Exploratory Study ◽  
Structural Joints

Tests and Modeling of a New Vibration Isolation and Suppression Device

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Zhao-Dong Xu ◽  
Yeshou Xu ◽  
Qianqiu Yang ◽  
Chao Xu ◽  
Feihong Xu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Energy Dissipation ◽  
Viscoelastic Material ◽  
Vibration Isolation ◽  
Dynamic Properties ◽  
Excitation Frequency ◽  
Dynamic Responses ◽  
Damping Capacity ◽  
Air Spring ◽  
Energy Dissipation Devices

Vibration is an environmental factor with hazardous effects on the instruments' precision, structural stability, and service life in engineering fields. Many kinds of energy dissipation devices have been invented to reduce the dynamic responses of structures and instruments due to environmental excitations. In this paper, a new kind of vibration isolation and suppression device with high damping performance, fine deformation recoverability, and bearing capacity for platform structures is developed, which is designed by considering the combination of the energy dissipation mechanisms of viscoelastic material, viscous fluid, and air spring. A series of dynamic properties tests on the device are carried out under different excitation frequencies and displacement amplitudes, and a mathematical model considering the coupling effects of energy dissipation of viscoelastic material, viscous liquid, and air spring is proposed. The research results indicate that the vibration isolation and suppression device has high damping capacity, and the proposed mathematical model can well describe the mechanical properties affected by excitation frequency and displacement amplitude.

Analysis of Bloch’s Method in Structures With Energy Dissipation

2010 ◽  
Author(s):  
Farhad Farzbod ◽  
Michael J. Leamy
Keyword(s):  
Energy Dissipation ◽  
Vibration Analysis ◽  
General Framework ◽  
Periodic Potential ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Periodic Systems ◽  
Crystalline Solid ◽  
Structural Damping ◽  
Electron Wave

Bloch analysis was originally developed to solve Schro¨dinger’s equation for the electron wave function in a periodic potential field, such as found in a pristine crystalline solid. In the context of Schro¨dinger’s equation, damping is absent and energy is conserved. More recently, Bloch analysis has found application in periodic macroscale materials, such as photonic and phononic crystals. In the vibration analysis of phononic crystals, structural damping is present together with energy dissipation. As a result, application of Bloch analysis is not straight-forward and requires additional considerations in order to obtain valid results. It is the intent of this paper to propose a general framework for applying Bloch analysis in such systems. Results are presented in which the approach is applied to example phononic crystals. These results reveal the manner in which damping affects dispersion and the presence of band gaps in periodic systems.

Research on Behavior of Ultra-High Toughness Cementitious Composites Reinforced Frame Joints

2011 ◽  
Vol 71-78 ◽  
pp. 794-798
Author(s):  
Jun Su ◽  
Shi Lang Xu ◽  
Dong Tao Xia
Keyword(s):  
Energy Dissipation ◽  
Carrying Capacity ◽  
Experimental Analysis ◽  
Experimental Results ◽  
Hysteretic Behavior ◽  
Cementitious Composites ◽  
Load Carrying Capacity ◽  
High Toughness ◽  
Load Carrying ◽  
Axial Compressive Ratio

In this article, through the seismic experimental analysis for six frame joints of ultra-high toughness cementitious composites, the load-carrying capacity, hysteretic behavior, energy dissipation and ductility of new joints are studied under different axial compressive ratio and the stirrups space. The experimental results show that the UHTCC joints have higher anti-cracking capacity and shear ductility. The UHTCC can reduce or even eliminate the amount of shear stirrups of the joint core. According to the analysis for the experiments, a theoretical calculating formula of shearing capacity is presented, whose calculating results agree well with the experimental results.

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