Identification of Impact Damping of Two Elastic Bodies

1999 ◽  
Author(s):  
Haiyan Hu ◽  
Dongping Jin
Keyword(s):  
Contact Force ◽  
Time History ◽  
Hertzian Contact ◽  
New Technique ◽  
Restoring Force ◽  
Nonlinear Spring ◽  
Elastic Bodies ◽  
Measured Time ◽  
The Impact ◽  
Impact Damping

Abstract The contact force of two impacting elastic bodies is widely modeled as the parallel combination of a nonlinear spring and a nonlinear dashpot. The restoring force of the nonlinear spring can be determined according to the Hertzian contact law in elasticity, while the model and corresponding parameters of the nonlinear damping force have to be identified through experiments. The current approaches of damping identification are based on the measured time histories of both contact force and relative approaching velocity of two impacting bodies. In this paper, a new technique is presented for the damping identification on the basis of measured time history of the contact force only. Hence, the tough problem of measuring the relative approaching velocity of two impacting bodies just before impact is removed. The efficacy test of the new technique is given in the paper through an example of identifying the impact damping of a pair of clamped beams.

scholarly journals Analysis of the Viscoelastic Sphere Impact against a Viscoelastic Uflyand-Mindlin Plate considering the Extension of Its Middle Surface

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yury A. Rossikhin ◽  
Marina V. Shitikova ◽  
Phan Thanh Trung
Keyword(s):  
Contact Force ◽  
Middle Surface ◽  
Hertzian Contact ◽  
Mindlin Plate ◽  
Strong Discontinuity ◽  
Time Duration ◽  
Suggested Approach ◽  
Viscoelastic Sphere ◽  
The Impact ◽  
Contact Domain

In the present paper, the problem on impact of a viscoelastic sphere against a viscoelastic plate is considered with due account for the extension of plate’s middle surface and local bearing of sphere and plate’s materials via the Hertz theory. The standard linear solid models with conventional derivatives and with fractional-order derivatives are used as viscoelastic models, respectively, outside and within the contact domain. As a result of impact, transient waves (surfaces of strong discontinuity) are generated in the plate, behind the wave fronts of which up to the boundaries of the contact domain the solution is constructed in terms of one-term ray expansions due to short-time duration of the impact process. The motion of the contact zone occurs under the action of extension forces acting in the plate’s middle surface, transverse force, and the Hertzian contact force. The suggested approach allows one to find the time-dependence of the impactor’s indentation into the target and the Hertzian contact force.

ANALYSIS OF ELASTIC IMPACT ON THIN SHELL STRUCTURES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1349-1354 ◽  
Author(s):  
SHIUH-CHUAN HER ◽  
CHING-CHUAN LIAO
Keyword(s):  
Differential Equation ◽  
Contact Force ◽  
Thin Shell ◽  
Time History ◽  
Dynamic Responses ◽  
Low Velocity Impact ◽  
Integro Differential Equation ◽  
Impact Process ◽  
Non Linear ◽  
The Impact

In this paper, a solution method for the response of a thin shell structure subjected to low velocity impact by a sphere is presented. The governing equation of the impact process is obtained by simultaneously solving the equations of motions for the sphere and shell. The derivation is based on the explicit expression of the displacement of the mid-surface of the shell under a single impulse load acting normal to apex of the shell. Incorporating the theory of convolution and Hertz contact law, a non-linear integro-differential equation in terms of the indentation of the contact, for the impact process is derived. The non-linear integro-differential equation is solved by the numerical scheme of Runge-Kutta method to obtain the time history of the contact force at the impact point of the shell. The contact force is then applied on the apex of the shell, the dynamic responses of the shell including the displacement and stress are obtained by the finite element method. The results are validated with the experimental test and numerical calculation published in the literatures. The effects of the radius and velocity of the impactor on the impact response is investigated through parametric study.

scholarly journals Analysis of the Dynamic Stiffness, Hysteresis Resonances and Complex Responses for Nonlinear Spring Systems in Power-Form Order

2021 ◽  
Vol 11 (16) ◽  
pp. 7722
Author(s):  
Qingtao Wang ◽  
Zhiyong Zhang ◽  
Yongheng Ying ◽  
Zhaojun Pang
Keyword(s):  
Normal Load ◽  
Dynamic Stiffness ◽  
Mechanical Systems ◽  
Contact Fatigue ◽  
Period Doubling ◽  
Excitation Amplitude ◽  
Hertzian Contact ◽  
Restoring Force ◽  
Nonlinear Spring ◽  
Stiffness Characteristics

Power-form nonlinear contact force models are widely adopted in relatively moving parts of macro (e.g., rolling bearings considering Hertzian contact restoring force between rolling elements and bearing raceways) or micro (e.g., the micro cantilever probe system of atomic force microscopy) scale mechanical systems, and contact resonance could cause serious problems of wear, contact fatigue, vibration, and noise, which has attracted widespread attention. In the present paper, the softening/hardening stiffness characteristics of continuous and one-sided contact power-form nonlinear spring models are addressed, respectively, by the analysis of the monotone features of resonant frequency-response skeleton lines. Herein, the period-n solution branch and its stability characteristics are obtained by the harmonic balance and alternating frequency/time domain (HB–AFT) method and Floquet theory. Compared with previous studies, this paper will furtherly clarify the influences of externally normal load, the power form exponent term, and excitation amplitude on the softening/hardening stiffness characteristics of general power-form spring systems. In addition, for a power-form system with a one-sided contact, the phenomena of primary and super/sub-harmonic hysteretic resonances inducing period-doubling, folding bifurcation, the coexistence of multiple solutions are demonstrated. Besides, it gives the evolution mechanism of two types of intermittency chaos in a one-sided contact system. The overall results may have certain basic theoretical significance and engineering values for the control of vibration and noise in contact mechanical systems.

Impact Analysis of Composite Laminate Shell Structures

2015 ◽  
Vol 764-765 ◽  
pp. 1185-1188 ◽  
Author(s):  
Shiuh Chuan Her ◽  
Ching Chun Liao
Keyword(s):  
Contact Force ◽  
Composite Laminate ◽  
Impact Analysis ◽  
Time History ◽  
Low Velocity Impact ◽  
Laminate Shell ◽  
Low Velocity ◽  
Runge Kutta Method ◽  
History Of ◽  
The Impact

In this investigation, the methodology for predicting the dynamic response of a composite laminate shell subjected to low velocity impact is presented. A non-linear integro-differential equation is derived and solved by the numerical scheme of Runge-Kutta method to obtain the time history of the contact force at the impact point of the shell. The contact force is then taken as external force acting on the apex of the shell and solved by the finite element method. The results are validated with the numerical calculation published in the literature.

scholarly journals Seismic Performance of a Green Roof Structure

2021 ◽  
Vol 13 (8) ◽  
pp. 4278
Author(s):  
Svetlana Tam ◽  
Jenna Wong
Keyword(s):  
Green Roof ◽  
Time History ◽  
Green Roofs ◽  
Moment Frame ◽  
Steel Moment Frame ◽  
Roof Structure ◽  
Nonlinear Time History Analyses ◽  
Vegetated Roofs ◽  
Nonlinear Time History ◽  
The Impact

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.

scholarly journals Detonation effects of shallow buried explosive in sandy soil on target plate acceleration in a small-scale blast test

2018 ◽  
Vol 192 ◽  
pp. 02028
Author(s):  
Hassan Zulkifli Abu ◽  
Ibrahim Aniza ◽  
Mohamad Nor Norazman
Keyword(s):  
Sandy Soil ◽  
High Speed ◽  
Early Stage ◽  
Time History ◽  
Video Camera ◽  
Small Scale ◽  
Target Plate ◽  
Air Blast ◽  
High Speed Video Camera ◽  
The Impact

Small-scale blast tests were carried out to observe and measure the influence of sandy soil towards explosive blast intensity. The tests were to simulate blast impact imparted by anti-vehicular landmine to a lightweight armoured vehicle (LAV). Time of occurrence of the three phases of detonation phase in soil with respect to upward translation time of the test apparatus were recorded using high-speed video camera. At the same time the target plate acceleration was measured using shock accelerometer. It was observed that target plate deformation took place at early stage of the detonation phase before the apparatus moved vertically upwards. Previous data of acceleration-time history and velocity-time history from air blast detonation were compared. It was observed that effects of soil funnelling on blast wave together with the impact from soil ejecta may have contributed to higher blast intensity that characterized detonation in soil, where detonation in soil demonstrated higher plate velocity compared to what occurred in air blast detonation.

scholarly journals Dynamics of Multibody Systems With Spherical Clearance Joints

2005 ◽  
Author(s):  
P. Flores ◽  
J. Ambro´sio ◽  
J. C. P. Claro ◽  
H. M. Lankarani
Keyword(s):  
Contact Force ◽  
Multibody Systems ◽  
Contact Forces ◽  
Force Model ◽  
Clearance Joints ◽  
Continuous Contact ◽  
Clearance Joint ◽  
Contact Force Model ◽  
Dynamics Of Multibody Systems ◽  
The Impact

This work deals with a methodology to assess the influence of the spherical clearance joints in spatial multibody systems. The methodology is based on the Cartesian coordinates, being the dynamics of the joint elements modeled as impacting bodies and controlled by contact forces. The impacts and contacts are described by a continuous contact force model that accounts for geometric and mechanical characteristics of the contacting surfaces. The contact force is evaluated as function of the elastic pseudo-penetration between the impacting bodies, coupled with a nonlinear viscous-elastic factor representing the energy dissipation during the impact process. A spatial four bar mechanism is used as an illustrative example and some numerical results are presented, being the efficiency of the developed methodology discussed in the process of their presentation. The results obtained show that the inclusion of clearance joints in the modelization of spatial multibody systems significantly influences the prediction of components’ position and drastically increases the peaks in acceleration and reaction moments at the joints. Moreover, the system’s response clearly tends to be nonperiodic when a clearance joint is included in the simulation.

Nonlinear Dynamic Analysis of the Damping Frame Structure System

2012 ◽  
Vol 594-597 ◽  
pp. 886-890 ◽  
Author(s):  
Gan Hong ◽  
Mei Li ◽  
Yi Zhen Yang
Keyword(s):  
Energy Dissipation ◽  
Seismic Response ◽  
Nonlinear Dynamic ◽  
Time History ◽  
Time History Analysis ◽  
Frame Structure ◽  
Force Model ◽  
Operating Characteristics ◽  
Restoring Force ◽  
History Analysis

Abstract. In the paper, take full account of energy dissipation operating characteristics. Interlayer shear-frame structure for the analysis of the Wilson-Θmethod ELASTOPLASTIC schedule, the design of a nonlinear dynamic time history analysis procedure. On this basis, taking into account the restoring force characteristics of the energy dissipation system, the inflection point in the restoring force model treatment, to avoid a result of the calculation results of distortion due to the iterative error. A frame structure seismic response time history analysis results show that: the framework of the energy dissipation significantly lower than the seismic response of the common framework, and its role in the earthquake when more significant.

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