Dynamic Behavior of Ideal Fibre-Reinforced Rigid-Plastic Beams

1976 ◽  
Vol 43 (2) ◽  
pp. 319-324 ◽  
Author(s):  
Norman Jones
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Dynamic Behavior ◽  
Isotropic Material ◽  
Structural Response ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Reinforced Beams ◽  
Dynamic Loadings

Theoretical solutions are developed herein for the dynamic plastic structural response of some ideal fibre-reinforced (strongly anisotropic) beams with boundary conditions and external dynamic loadings which can be reproduced easily and reliably in a laboratory. The theoretical behavior of these beams is also compared to the corresponding dynamic response of beams which are made from a rigid perfectly plastic isotropic material. Generally speaking, it appears that the permanent transverse deflections and response durations of ideal fibre-reinforced beams loaded dynamically are less than the corresponding values for similar rigid perfectly plastic isotropic beams.

Dynamic Response of Blast-Loaded Stiffened Plates by Rigid-Plastic Analysis

2010 ◽  
Author(s):  
Ping Yang ◽  
Ying Peng
Keyword(s):  
Dynamic Response ◽  
Yield Curve ◽  
Bending Moment ◽  
Stiffened Plates ◽  
Flow Rule ◽  
Beam Model ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Load Intensity ◽  
Plastic Flow Rule

The dynamic response of one-way stiffened plates with clamped edges subjected to uniformly distributed blast-induced shock loading is theoretically investigated using a singly symmetric beam model. The beam model is based on the rigid-perfectly plastic assumption. The bending moment-axial force capacity interaction relation or yield curve for singly symmetric cross-section is derived and explicitly presented. The deflection condition that a plastic string response must satisfy is determined by the linearized interaction curve and associated plastic flow rule. Moreover, the possible motion mechanisms of the beam are discussed under different load intensity. Finally the dynamic response of a one-way stiffened plate is calculated theoretically and numerically. Good agreements are obtained between the presented theoretical results and those from numerical calculations of the FEM software ANSYS and ABAQUS/Explicit. It is concluded that the basic assumptions and approximations for simplifying calculations are reasonable and the beam model in theoretical analysis is adoptable. The example also shows that an arbitrary blast load can be replaced equivalently by a rectangular type pulse.

Theory of Viscoplastic Shells for Dynamic Response

1983 ◽  
Vol 50 (1) ◽  
pp. 131-136 ◽  
Author(s):  
R. S. Atkatsh ◽  
M. P. Bieniek ◽  
I. S. Sandler
Keyword(s):  
Dynamic Response ◽  
Shell Model ◽  
Constitutive Equations ◽  
Structural Response ◽  
Acoustic Medium ◽  
Stress Resultant ◽  
Shell Analysis ◽  
Dynamic Loadings ◽  
Elastoplastic Shell ◽  
Dynamic Variables

A viscoplastic shell model is formulated that utilizes the shell membrane strains and curvatures as the kinematic variables and the shell stress resultants (membrane forces and moments) as the dynamic variables. The viscoplastic shell model combines the concepts of Perzyna’s viscoplastic constitutive equations with Bieniek’s shell stress resultant formulation. The model is incorporated into the Elastoplastic Shell Analysis code (EPSA) for the analysis of shells in an acoustic medium subjected to dynamic loadings that produce moderately large elastoviscoplastic deformations in the shell. An example is presented to demonstrate the effect of material rate dependence on structural response.

Flow Induced Vibration of Large Deflection Filament in Viscous Flow

2005 ◽  
Author(s):  
Cosmas P. Pagwiwoko ◽  
Tim David ◽  
Elijah Van Houten
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Large Deflection ◽  
Stokes Equations ◽  
Density Ratio ◽  
Structural Response ◽  
Time Step ◽  
Integration Algorithm ◽  
Flowing Fluid ◽  
Fluid Structure

This work presents a numerical simulation of fluid-structure interaction of a highly flexible filament in a flow. A finite element model of nonlinear/large deflection cantilever beam is developed to represent the filament. The flow of Newtonian fluid is considered laminar and two-dimensional. The coupling of fluid-structure is carried out by using the fictitious domain algorithm where the moving boundary conditions are imposed. A no-slip condition is applied to all boundary conditions included on the surface of the moving filament. The structural response is calculated at one time step behind the solution of the Navier-Stokes equations. The additional mass plays an important role in dynamic response especially when the density ratio between the fluid and the filament becomes considerably high. To prevent the numerical instability, the equation of motion needs to be represented in a non-dimensional form by keeping the similarities of flow and dynamic response. A ramp function model is applied to simulate the gradual growth of fluid dynamic loads. In the structural part, a Crank-Nicholson integration algorithm is used in calculating the simultaneous structural response. The validation of the method was carried out through the existing experimental results for low density ratio of flowing fluid and filament material in wind-tunnel test, and for high density ratio in flowing soap test as well.

scholarly journals Time-Frequency Energy Distribution of Ground Motion and Its Effect on the Dynamic Response of Nonlinear Structures

2019 ◽  
Vol 11 (3) ◽  
pp. 702 ◽  
Author(s):  
Dongwang Tao ◽  
Jiali Lin ◽  
Zheng Lu
Keyword(s):  
Dynamic Response ◽  
Energy Distribution ◽  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Structural Response ◽  
Ground Acceleration ◽  
Time Frequency ◽  
Plastic Structure ◽  
Perfectly Plastic ◽  
Frequency Components

The ground motion characteristics are essential for understanding the structural seismic response. In this paper, the time-frequency analytical method is used to analyze the time-frequency energy distribution of ground motion, and its effect on the dynamic response of nonlinear structure is studied and discussed. The time-frequency energy distribution of ground motion is obtained by the matching pursuit decomposition algorithm, which not only effectively reflects the energy distribution of different frequency components in time, but also reflects the main frequency components existing near the peak ground acceleration occurrence time. A series of artificial ground motions with the same peak ground acceleration, Fourier amplitude spectrum, and duration are generated and chosen as the earthquake input of the structural response. By analyzing the response of the elasto-perfectly-plastic structure excited by artificial seismic waves, it can be found that the time-frequency energy distribution has a great influence on the structural ductility. Especially if there are even multiple frequency components in the same ground motion phrase, the plastic deformation of the elasto-perfectly-plastic structure will continuously accumulate in a certain direction, resulting in a large nonlinear displacement. This paper reveals that the time-frequency energy distribution of a strong ground motion has a vital influence on the structural response.

Counterintuitive Dynamic Behavior in Elastic-Plastic Structures

2012 ◽  
Vol 428 ◽  
pp. 47-51 ◽  
Author(s):  
Yong Gang Zhao ◽  
Xiao Peng Yan ◽  
Gui Tong Yang
Keyword(s):  
Dynamic Response ◽  
Dynamic Behavior ◽  
Circular Plate ◽  
Formation Mechanism ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Square Plate ◽  
The Law ◽  
Elastic Perfectly Plastic ◽  
Lyapunov Instability

The counterintuitive phenomena of elastic, perfectly plastic beam, circular plate and square plate are investigated numerically and experimentally. A new unstable slot and asymmetry of dynamic response of beam are revealed. The unsteady areas and uncertainty of response are observed numerically. At the end, the law of thermodynamics and the theorem of Lyapunov instability are employed to state the formation mechanism of counterintuitive behavior.

Influence of the backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set

2016 ◽  
Vol 231 (11) ◽  
pp. 2025-2041 ◽  
Author(s):  
Shijing Wu ◽  
Haibo Zhang ◽  
Xiaosun Wang ◽  
Zeming Peng ◽  
Kangkang Yang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Planetary Gear ◽  
Tooth Wear ◽  
Transmission Error ◽  
Gear Transmission ◽  
Tooth Surface ◽  
Contact Ratio ◽  
The Impact

Backlash is a key internal excitation on the dynamic response of planetary gear transmission. After the gear transmission running for a long time under load torque, due to tooth wear accumulation, the backlash between the tooth surface of two mating gears increases, which results in a larger and irregular backlash. However, the increasing backlash generated by tooth accumulated wear is generally neglected in lots of dynamics analysis for epicyclic gear trains. In order to investigate the impact of backlash generated by tooth accumulated wear on dynamic behavior of compound planetary gear set, in this work, first a static tooth surface wear prediction model is incorporated with a dynamic iteration methodology to get the increasing backlash generated by tooth accumulated wear for one pair of mating teeth under the condition that contact ratio equals to one. Then in order to introduce the tooth accumulated wear into dynamic model of compound planetary gear set, the backlash excitation generated by tooth accumulated wear for each meshing pair in compound planetary gear set is given under the condition that contact ratio equals to one and does not equal to one. Last, in order to investigate the impact of the increasing backlash generated by tooth accumulated wear on dynamic response of compound planetary gear set, a nonlinear lumped-parameter dynamic model of compound planetary gear set is employed to describe the dynamic relationships of gear transmission under the internal excitations generated by worn profile, meshing stiffness, transmission error, and backlash. The results indicate that the introduction of the increasing backlash generated by tooth accumulated wear makes a significant influence on the bifurcation and chaotic characteristics, dynamic response in time domain, and load sharing behavior of compound planetary gear set.

DYNAMIC BEHAVIOR OF TELESCOPIC CRANES BOOM

2013 ◽  
Vol 13 (01) ◽  
pp. 1350010 ◽  
Author(s):  
IOANNIS G. RAFTOYIANNIS ◽  
GEORGE T. MICHALTSOS
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Dynamic Behavior ◽  
Analytical Model ◽  
Constant Velocity ◽  
Steel Beam ◽  
Continuum Approach ◽  
Theoretical Formulation ◽  
Modal Superposition ◽  
Superposition Technique

Telescopic cranes are usually steel beam systems carrying a load at the tip while comprising at least one constant and one moving part. In this work, an analytical model suitable for the dynamic analysis of telescopic cranes boom is presented. The system considered herein is composed — without losing generality — of two beams. The first one is a jut-out beam on which a variable in time force is moving with constant velocity and the second one is a cantilever with length varying in time that is subjected to its self-weight and a force at the tip also changing with time. As a result, the eigenfrequencies and modal shapes of the second beam are also varying in time. The theoretical formulation is based on a continuum approach employing the modal superposition technique. Various cases of telescopic cranes boom are studied and the analytical results obtained in this work are tabulated in the form of dynamic response diagrams.

Dynamic Behavior of Aircraft Wings Modeled as Doubly-Tapered Composite Thin-Walled Beams

1999 ◽  
Author(s):  
Sungsoo Na ◽  
Liviu Librescu
Keyword(s):  
Composite Materials ◽  
Free Vibration ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Transverse Shear ◽  
Dynamical Behavior ◽  
Time Dependent ◽  
Aircraft Wings ◽  
Helicopter Blades ◽  
Thin Walled

Abstract A study of the dynamical behavior of aircraft wings modeled as doubly-tapered thin-walled beams, made from advanced anisotropic composite materials, and incorporating a number of non-classical effects such as transverse shear, and warping inhibition is presented. The supplied numerical results illustrate the effects played by the taper ratio, anisotropy of constituent materials, transverse shear flexibility, and warping inhibition on free vibration and dynamic response to time-dependent external excitations. Although considered for aircraft wings, this analysis and results can be also applied to a large number of structures such as helicopter blades, robotic manipulator arms, space booms, tall cantilever chimneys, etc.

Application of viscous dampers for structural response reduction in building renovation

2021 ◽  
Author(s):  
Hu Daohang ◽  
Zhao Xin
Keyword(s):  
Dynamic Response ◽  
Structural Response ◽  
Seismic Energy ◽  
Original Structure ◽  
Viscous Dampers ◽  
Structural Reinforcement ◽  
Analysis Methods ◽  
Direct Integration Method ◽  
Calculation Results ◽  
Plane Frame

<p>This paper introduces a new idea in the reconstruction and continuation projects. By arranging damping devices, the additional damping of the structure is increased, thereby reducing the dynamic response of the structure under the new seismic precautionary criterion. This paper focuses on the study of viscous dampers which one of the damping device, introduces the energy dissipation principle of viscous dampers, and combines a two-story plane frame case to analyze and compare the dynamic response between non-damping structure and damping structure. The location and quantity of the arrangement were compared with multiple models. Through analysis, it can be seen that by equipping with viscous dampers, seismic energy can be effectively dissipated, thereby reducing the workload of structural reinforcement and having less impact on the original structure. Finally, two commonly analysis methods in damping structures are studied, direct integration method and fast nonlinear analysis (FNA), the main differences between the two analysis methods are introduced, and the calculation results of the two methods are compared and analyzed.</p>

Dynamics and Control of Dual-Hoist Cranes Moving Triangular Payloads

2014 ◽  
Author(s):  
Alexander S. Miller ◽  
Padma Sarvepalli ◽  
William Singhose
Keyword(s):  
Dynamic Response ◽  
Dynamic Behavior ◽  
Bridge Crane ◽  
Response Characteristics ◽  
Dynamics And Control ◽  
System Configurations ◽  
And Control

Certain heavy-lifting applications require the coordinated movement of multiple cranes. Such tasks dramatically increase the complexity of crane operation, especially when the payload has a non-uniform shape. This paper studies the dynamic behavior of a dual-hoist bridge crane moving triangular payloads. Simulations and experiments are used to develop an understanding of the dynamic response of the system. Various inputs and system configurations are analyzed, and important response characteristics are highlighted.

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