The Influence of Nonhomogeneous Interlayer Stiffness on Dynamic Response of Orbit-Girder System under Moving Load

2021 ◽  
pp. 2250004
Author(s):  
Shaohui Liu ◽  
Lizhong Jiang ◽  
Wangbao Zhou ◽  
Yuntai Zhang ◽  
Yulin Feng ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Moving Load ◽  
Distribution Patterns ◽  
Stiffness Degradation ◽  
Factors Affecting ◽  
Nonlinear Fitting ◽  
Fourier Series Method ◽  
Stiffness Distribution ◽  
Peak Value

Based on the finite Fourier series method and the principle of energy variation, a method for calculating the dynamic response of an orbit-girder system is proposed, which is suitable for general spring boundary and nonhomogeneous interlayer stiffness distribution. Two numerical examples are given to verify the effectiveness of the proposed method under different moving load speeds and different stiffness distribution patterns. Based on this method, the influence of boundary conditions, interlayer stiffness degradation mode and degradation amplitude as well as the motion load on the dynamic response of the orbit-girder system is analyzed. A formula for calculating the peak value of additional dynamic response caused by interlayer stiffness degradation is proposed based on the nonlinear fitting method, and the factors affecting the additional response are analyzed. Results show that the variation of boundary conditions does not affect the additional dynamic response of the orbit-girder system. The mode of interlayer stiffness degradation and the degree of nonhomogeneous distribution have a significant influence on the peak of additional dynamic response. The additional dynamic response peak value of the orbit-girder system increases significantly with an increasing degree of nonhomogeneous degradation of the interlayer stiffness. The orbit-girder system has multiple critical speeds under the action of moving load. The magnitude of moving load has an important effect on the additional response peaks of the orbit-girder system. The additional response peaks increase approximately linearly with the increase of the motion load.

Random Base Excitation of Timoshenko Beam Traversed by Moving Load

2011 ◽  
Author(s):  
Fahim Javid ◽  
Ebrahim Esmailzadeh ◽  
Davood Younesian
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Boundary Conditions ◽  
Timoshenko Beam ◽  
Moving Load ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Base Excitation ◽  
Lateral Direction ◽  
Beam Dynamic

The study of dynamic response of Timoshenko beam traversed by moving load subjected to random base excitation is carried out. By applying the theory of dynamic response of Timoshenko beam as well as finite element theory, beam finite element governing equations of motion are developed and they are solved using Galerkin method. To validate the model, some results of the model are compared with those available in literatures and very close agreement is achieved. The beam is subjected to travelling load and random base excitation in lateral direction simultaneously. Three types of boundary conditions, namely, hinged-hinged, hinged-clamped, and the clamped-clamped ends, are considered and beam dynamic behavior; such as deflection, velocity, and bending moment of beam midpoint, with all so-called boundary conditions are studied. To get better understanding of base excitation effects on the beam dynamic performance, all the results are presented with and without base excitation, in which considerably difference is observed. Moreover, the effect of base excitation on beam with different span-length is monitored.

Dynamic Response of a Spinning Timoshenko Beam With General Boundary Conditions and Subjected to a Moving Load

1994 ◽  
Vol 61 (1) ◽  
pp. 152-160 ◽  
Author(s):  
J. W.-Z. Zu ◽  
R. P. S. Han
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Timoshenko Beam ◽  
Moving Load ◽  
Original System ◽  
Adjoint System ◽  
General Boundary ◽  
General Boundary Conditions ◽  
Adjoint Systems ◽  
Analysis Technique

The dynamic response of a spinning Timoshenko beam with general boundary conditions and subjected to a moving load is solved analytically for the first time. Solution of the problem is achieved by formulating the spinning Timoshenko beams as a non-self-adjoint system. To compute the system dynamic response using the modal analysis technique, it is necessary to determine the eigenquantities of both the original and adjoint systems. In order to fix the adjoint eigenvectors relative to the eigenvectors of the original system, the biorthonormality conditions are invoked. Responses for the four classical boundary conditions which do not involve rigidbody motions are illustrated. To ensure the validity of the method, these results are compared with those from Euler-Bernoulli and Rayieigh beam theories. Numerical simulations are performed to study the influence of the four boundary conditions on selected system parameters.

The Influence of Velocity of Moving Load on the Rail Dynamic Response

2012 ◽  
Vol 482-484 ◽  
pp. 1402-1405 ◽  
Author(s):  
Zhi Hui Huang ◽  
Qing Guang Chen ◽  
Yi Gang Li ◽  
Liang Lin Shi
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Mechanical Model ◽  
Moving Load ◽  
Superposition Method ◽  
Load Range ◽  
Model Combining ◽  
Load Increase ◽  
Method Analysis ◽  
Oscillation Equation

In order to study the relation between the velocity of moving load and the rail deformation, a mechanical model about rail elastic support was built for a existing wheel/rail system monitoring equipment's physical model. Combining the boundary conditions and load type, the oscillation equation of rail mechanical model was solved via Vibration superposition method. Analysis the dynamic response of rail under different moving load range from 40km/h to 200km/h by MATLAB.The law of the relation between rail deformation and the velocity of moving load was got. That is the deformation of rail decrease when the velocity of the moving load increase.

scholarly journals Distribution Patterns of Odonate Assemblages in Relation to Environmental Variables in Streams of South Korea

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 152 ◽  
Author(s):  
Da-Yeong Lee ◽  
Dae-Seong Lee ◽  
Mi-Jung Bae ◽  
Soon-Jin Hwang ◽  
Seong-Yu Noh ◽  
...  
Keyword(s):  
Land Use ◽  
Ecosystem Services ◽  
Environmental Factors ◽  
South Korea ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Environmental Changes ◽  
Distribution Patterns ◽  
Self Organizing Map ◽  
Factors Affecting

Odonata species are sensitive to environmental changes, particularly those caused by humans, and provide valuable ecosystem services as intermediate predators in food webs. We aimed: (i) to investigate the distribution patterns of Odonata in streams on a nationwide scale across South Korea; (ii) to evaluate the relationships between the distribution patterns of odonates and their environmental conditions; and (iii) to identify indicator species and the most significant environmental factors affecting their distributions. Samples were collected from 965 sampling sites in streams across South Korea. We also measured 34 environmental variables grouped into six categories: geography, meteorology, land use, substrate composition, hydrology, and physicochemistry. A total of 83 taxa belonging to 10 families of Odonata were recorded in the dataset. Among them, eight species displayed high abundances and incidences. Self-organizing map (SOM) classified sampling sites into seven clusters (A–G) which could be divided into two distinct groups (A–C and D–G) according to the similarities of their odonate assemblages. Clusters A–C were characterized by members of the suborder Anisoptera, whereas clusters D–G were characterized by the suborder Zygoptera. Non-metric multidimensional scaling (NMDS) identified forest (%), altitude, and cobble (%) in substrata as the most influential environmental factors determining odonate assemblage compositions. Our results emphasize the importance of habitat heterogeneity by demonstrating its effect on odonate assemblages.

Dynamic Test of Bird Strike on a Flat Plate Made from LY-12 Aluminium

2013 ◽  
Vol 765-767 ◽  
pp. 3158-3161
Author(s):  
Jun Liu ◽  
Zheng Li Zhang
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Dynamic Test ◽  
Time History ◽  
Aircraft Design ◽  
Bird Strike ◽  
Test Results ◽  
Valuable Data ◽  
Good Agreement ◽  
Peak Value

Tests of bird strike have been carried out on plate made from LY-12 Aluminium. The test was down with the projectile impacting the target perpendicularly at velocity of 40m/s, 80m/s, 120m/s respectively. The displacement-time history curves and strain-time history curves of on LY-12 Aluminium plate were measured. The good agreement of the results between two specimens in one group indicated that the results tested in the presnet paper are reliable. The dynamic response of the plate and damage modes of the bird influenced by striking velocity were analyzed. The peak value of the displacement linear enlarged with the increasing of the striking velocity. The test results in the present paper provided valuable data for aircraft design impacted by bird, and also provided abundant test datas for the numerical simulation model applied in bird striking.

Sign in / Sign up

Export Citation Format

Share Document