scholarly journals Study on Development Law of Mining-Induced Slope Fracture in Gully Mining Area

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Tao Yang ◽  
Yiran Yang ◽  
Jie Zhang ◽  
Shoushi Gao ◽  
Tong Li
Keyword(s):  
Mining Area ◽  
Force Model ◽  
Beam Model ◽  
Beam Structure ◽  
Distributed Load ◽  
Load Beam ◽  
Fracture Development ◽  
Nonuniform Load ◽  
Induced Fractures ◽  
Step Distance

The development law of mining cracks in shallow coal seams under gully topography was used as the research base to analyze the development characteristics of mining cracks in the 5-2 coal mining face of Anshan Coal Mine, and the weak strength was established. The basic top force model under the action of the overburden is the “nonuniformly distributed load beam” structure model. Through similar simulation research and theoretical calculation analysis, the fracture development law of the working face passing through the valley is studied. Based on the mechanical analysis of the beam structure with nonuniform load, the discriminant conditions of the stability of the bearing structure of the bedrock are derived, the calculation formulas of the parameters such as the pressure, shear force, and the ultimate span of the basic roof at both ends are determined, the influence law of the thickness and slope change of the weak strength overburden on the mining crack spacing is revealed, and the influence of the slope of the weak strength overburden on the weighting step distance on the beam with nonuniform load is obtained. The phenomenon is that the burial depth has a great influence on the step distance of weighting. The practice shows that the distance between the mining-induced fractures determined by the nonuniformly distributed load beam model and the periodic weighting step, the height of fracture development, and the buried depth are approximately the same; the mining-induced fractures in the overburden develop and evolve periodically with the failure and instability of the bedrock. The research results will clarify the development mechanism of surface cracks in the gully mining area, which is of great significance to reduce terrain disasters.

Response of a Rotating Beam Subject to an Accelerating Force

1991 ◽  
Author(s):  
A. Argento ◽  
R. A. Scott
Keyword(s):  
Constant Velocity ◽  
Integral Transforms ◽  
Beam Model ◽  
Rotating Beam ◽  
Velocity Function ◽  
Distributed Load ◽  
Fixed Direction ◽  
Convolution Integrals ◽  
Rotating Timoshenko Beam ◽  
Set Up

Abstract A method is given by which the response of a rotating Timoshenko beam subjected to an accelerating fixed direction force can be determined. The beam model includes the gyroscopically induced displacement transverse to the direction of the load. The solution for pinned supports is set up in general form using multi-integral transforms and the inversion is expressed in terms of convolution integrals. These are numerically integrated for a uniformly distributed load having an exponentially varying velocity function. Results are presented for the displacement under the load’s center as a function of position. Comparisons are made between the responses to a constant velocity load and a load which accelerates up to the same velocity.

Dynamic response of bridges under travelling loads

1993 ◽  
Vol 20 (2) ◽  
pp. 287-298 ◽  
Author(s):  
J. L. Humar ◽  
A. M. Kashif
Keyword(s):  
Dynamic Response ◽  
Rational Design ◽  
Weight Ratio ◽  
Experimental Investigations ◽  
Speed Ratio ◽  
Force Model ◽  
Beam Model ◽  
Dynamic Amplification Factor ◽  
Design Procedures ◽  
Dynamic Amplification

In spite of a number of analytical and experimental investigations on the dynamic response of bridges to moving vehicle loads, the controlling parameters that govern the response have not been clearly identified. This has, in turn, inhibited the development of rational design procedures. Based on an analytical investigation of the response of a simplified beam model traversed by a moving mass, the present study identifies the governing parameters. The results clearly show why attempts to correlate the response to a single parameter, either the span length or the fundamental frequency, are unsuccessful. Simple design procedures are developed based on relationships between the speed ratio, the weight ratio, and the dynamic amplification factors; and a set of design curves are provided. Key words: dynamic response of bridges, vehicle–bridge interaction, moving force model, moving sprung mass model, dynamic amplification factor.

scholarly journals Analysis of Rigid Body Swing Effect on SCR Response under Top Motion and Wave Action

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Bo Zhu ◽  
Weiping Huang ◽  
Zhenwen Sun ◽  
Xinglong Yao ◽  
Juan Liu
Keyword(s):  
Rigid Body ◽  
Flow Direction ◽  
Vertical Direction ◽  
Wave Force ◽  
Wave Action ◽  
Force Model ◽  
Beam Model ◽  
Wave Load ◽  
Steel Catenary Riser ◽  
Cross Direction

The catenary riser such as steel catenary riser (SCR), under wave action or current action, shows a kind of rotation that acts as a rigid body along a similarly fixed axis of oscillation determined by the varying suspension and touch down point, respectively. The characteristics of acceleration of catenary riser influenced by rigid body swing integrity backwards and forwards (RBSIBF) in cross direction cannot be neglected. Based on the large deflection slender beam model, top motion of x direction, RBSIBF, and wave force model, this manuscript studies and explains effect of RBSIBF in cross direction (z direction) on riser in quantitative and qualitative perspectives. The rigid body wiggle effect can be considered by amplitude-value multiplication with the safety factor of 1.2. The calculation shows that, in terms of the overall motion pattern, the motion response in the xy plane develops gradually from the narrow amplitude wiggle in in-line direction of top region to narrow amplitude wiggle in vertical direction of bottom area. Wave load is the main effect load in cross-flow direction. Along the depth increase, the acceleration amplitude of the top hanging point area is maximum, and the amplitude decreases most strongly or violently. With the decrease of case amplitude, the structural acceleration responses of node 10th to 80th significantly reduced by about 30% and the corresponding of node 140th to 200th increased by about 15%. The most influential point of RBSIBF on acceleration is node 200th with an influence level of about 20%. When the structure mainly rotates in the xz plane, rigid body wiggle and swing are positively correlated with rotation vector diameter. The rigid body wiggle and swing increase acceleration of structure. In the rotational yz plane of the structure, rigid body wiggle and swing reduce acceleration response.

Cutting Force and Tool Deflection Predictions for High Speed Machining of Hard to Cut Material

2010 ◽  
Vol 154-155 ◽  
pp. 1157-1164 ◽  
Author(s):  
Jinn Jong Sheu ◽  
Dong Mei Xu ◽  
Chin Wei Liu
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
High Speed ◽  
Force Model ◽  
Beam Model ◽  
High Speed Machining ◽  
Tool Deflection ◽  
Machining Center ◽  
Helical Angle ◽  
Cutting Experiment

The dimension accuracy and the too life are the major issues of the machining of hard-to-cut materials. To fulfill the requirements of accuracy and tool life needs not only well planning of cutting path but also the proper cutting conditions of cutters. The vibration and deflection of cutters caused by poor selection of cutting conditions can be predicted using models of cutting force and tool deflection. In this paper, a cutting force model considering the effect of tool helical angle and a cantilever beam model of tool deflection were proposed for the high speed machining of hard-to-cut material SKD11. The shearing force, the plowing forces, and the helical angle of cutters are considered in the elemental force model. The material of workpiece, SKD11, studied in this paper is commonly used for the die and mold industries. The cutting constants of the proposed force model are determined via the cutting experiments carried out on a high speed machining center. A dynamometer and a high frequency data acquisition system were used to measure the x-, y-, and z-direction cutting forces. The obtained cutting constants were used to predict the cutting forces and compared with the results obtained from the cutting experiment of verification using cutters with different helical angles. The theoretical and the experimental cutting forces in the x-, y-, and z- direction are in good agreement using flat cutters with 30 and 45 degrees of helical angle. The dimension deviations of the cut surface in the cutting experiment case of tool deflection were measured using a touch probe and an infrared receiver installed on the machining center. The measured average dimension deviation, 0.163mm, is close to the predicted tool deflection, 0.153mm, using the proposed cantilever beam model. The comparisons of the cutting forces and the average of the cut surface dimension deviation are in good agreement and verify the proposed cutting force and the tool deflection models are feasible and useful.

The Application of Multiaxial Fabric Blower Blade and its Strength Theory Check

2012 ◽  
Vol 476-478 ◽  
pp. 2586-2589
Author(s):  
Zhi Yun Wu ◽  
Chun Fang Zhang
Keyword(s):  
High Strength ◽  
Speed Ratio ◽  
Force Model ◽  
Blade Design ◽  
Strength Theory ◽  
Beam Structure ◽  
Tip Speed Ratio ◽  
Extended Length ◽  
Design And Manufacture ◽  
Made In

The scale application of wind energy conforms to the demand of sustainable development in our country. However, with the blower’s blade lengthened, the weight will also increase. If it is made in traditional way, it would reach tons of orders of magnitude, and the centrifugal force on the blade root will become very large because of the tip speed ratio. When the wind is large enough, the blade force model is equivalent to a cantilever beam structure, thus the material of extended wind turbine blade should possess high strength and high modulus and should be light. Otherwise the blade’s life will be shortened [1]. In many of the materials, the multi-axial fabric is a good carrier to meet these requirements. If the blade in the extended length also can meet the strength requirements, the multi-axial fabric will be the top choice for future wind-driven generator blade design and manufacture.

Simulated Analysis for Strengthening RC Beam Bonding with External Steel Plate

2010 ◽  
Vol 163-167 ◽  
pp. 3745-3748
Author(s):  
Lan Ying Wu ◽  
Yan Lin Wang ◽  
Fang Hong
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Steel Plate ◽  
Limit Load ◽  
Reinforced Concrete Beam ◽  
Beam Structure ◽  
Concentrated Load ◽  
Distributed Load ◽  
Element Simulation

Based on the reinforced concrete beam structure bonding with steel plate are consisted of different materials, the finite element model of the reinforced concrete beam structure bonding with steel plate was established using the whole model and the separated model respectively, the deformation, stress, strain and limit load of the reinforced concrete beam structure under the symmetrical concentrated load and the uniformly distributed load were studied using ANSYS. The research results show that the limit load value based on the finite element simulation is basically equal with the experimental value, there has little error between them, but within the scope of control in error, and the limit load under the uniformly distributed load is greater than the symmetrical concentrated load; The results from the whole model and the separated model are basically equal with the experimental results, which show that it’s feasible using the finite element simulation to analyze the reinforced concrete beam structure bonding with steel plate.

Period-Doubling Bifurcations in Atomic Force Microscopy

2009 ◽  
Author(s):  
Andrew J. Dick ◽  
Wei Huang
Keyword(s):  
Dynamic Response ◽  
Atomic Force Microscope ◽  
Period Doubling ◽  
Surface Force ◽  
Resonance Excitation ◽  
Force Model ◽  
Beam Model ◽  
Atomic Force ◽  
Local Material ◽  
Local Material Properties

The dynamic response of an atomic force microscope cantilever probe is studied for off-resonance excitation and interactions with a soft silicone rubber material. The dynamic response of the probe is simulated using a three-mode approximation of the Euler-Bernoulli beam model for excitation at two-and-a-half times the probe’s fundamental frequency. These simulations are conducted in order to reproduce the period-doubling bifurcation experimentally observed in the response of the probe of a commercial atomic force microscope. In order to duplicate this behavior, parameters within the surface force model are tuned to account for variations in the characteristics of the sample material. Through this work, the relationship between the sample material’s effective stiffness and the response behavior of the probe are studied in an effort to develop the means to identify the local material properties of a sample by characterize the nonlinear response of the probe.

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