Force Method Of Analysis Research Articles

An Updated Analytical Structural Pounding Force Model Based on Viscoelasticity of Materials

Based on the summary of existing pounding force analytical models, an updated pounding force analysis method is proposed by introducing viscoelastic constitutive model and contact mechanics method. Traditional Kelvin viscoelastic pounding force model can be expanded to 3-parameter linear viscoelastic model by separating classic pounding model parameters into geometry parameters and viscoelastic material parameters. Two existing pounding examples, the poundings of steel-to-steel and concrete-to-concrete, are recalculated by utilizing the proposed method. Afterwards, the calculation results are compared with other pounding force models. The results show certain accuracy in proposed model. The relative normalized errors of steel-to-steel and concrete-to-concrete experiments are 19.8% and 12.5%, respectively. Furthermore, a steel-to-polymer pounding example is calculated, and the application of the proposed method in vibration control analysis for pounding tuned mass damper (TMD) is simulated consequently. However, due to insufficient experiment details, the proposed model can only give a rough trend for both single pounding process and vibration control process. Regardless of the cheerful prospect, the study in this paper is only the first step of pounding force calculation. It still needs a more careful assessment of the model performance, especially in the presence of inelastic response.

Optimization of Shaft Sleeve Slippage in High-Voltage Circuit Breaker Operation Mechanism

High-voltage circuit breakers are mechanical switching devices which connect and break current circuits (operating currents and fault currents) and carry the nominal current in closed position. As a result of multi-running, the shaft sleeve in operation mechanism could slip and even strip from the shaft at the hinge joint, which decreases the system reliability. In this work, investigations on the cause of sleeve slippage are proceeded, and the dimension parameters of shafting components where sleeve slippage occurs are optimized by incorporating a quasi-static mechanical model with Taguchi method. By developing and analyzing the mechanical model for the shaft sleeve slippage, it indicates that the sleeve slippage displacement has a same variation tendency with the shaft deflection. Theoretical equations are derived by using force analysis and superposition method to descript the analytic function of the shaft deflection. As the variables within the analytic function of the shaft deflection, the diameter and length of the shaft and the corresponding shaft sleeve length are selected as the control parameters in the optimization model. Moreover, several experiments are conducted by using the L18 (mixed orthogonal array) design method. Considering that the local mechanical characteristics such as sleeve strain are difficult to monitor via experimental method, an FEM simulation model is established to give the sleeve slippage displacement. Different levels of control parameters are introduced into the mechanical model and FEM simulation according to Taguchi method. The results from signal-to-noise (S/N) and ANOVA analysis (analysis of variance) reveal that shaft diameter is the most significant factor determining sleeve slippage in high-voltage circuit breaker operation mechanism, and that a larger diameter of shaft, a shorter shaft length and a longer sleeve length can reduce the sleeve slippage effectively. Meanwhile, the theoretical model is verified and enhanced by the FEM model.

A Thrust Force Analysis Method for Permanent Magnet Linear Motor Using Schwarz–Christoffel Mapping and Considering Slotting Effect, End Effect, and Magnet Shape

A Schwarz–Christoffel (SC) mapping-based method is presented for accurately and efficiently predicting the thrust force of permanent magnet linear motors (PMLMs). It accounts for not only the slotting effect but also the end effect and the magnet shape. In this method, according to the magnet shape, the PMs are modeled as equivalent line currents on their surfaces. Through analyzing the invariant of the governing Poissonian field equation of line currents under a conformal mapping, the magnetic field boundary value problem in the air gap is mapped to a rectangle by the SC mapping, which is calculated with the SC Toolbox of MATLAB. Furthermore, the magnetic field solution is constructed with the line currents in a strip under the flux continuity condition. The cogging force due to the slotting effect and the end effect is obtained, respectively, by integrating the Maxwell stress tensor along the lines closely surrounding the slotted and finite-length iron core. The validity of the proposed method is examined by the finite-element method. The influences of the magnet shape on the thrust force pulsation characteristic are investigated for a PMLM equipped with rectangular PM and bread loaf PM.

Constraint force analysis of metamorphic joints based on the augmented Assur groups

In order to obtain a simple way for the force analysis of metamorphic mechanisms, the systematic method to unify the force analysis approach of metamorphic mechanisms as that of conventional planar mechanisms is proposed. A force analysis method of metamorphic mechanisms is developed by transforming the augmented Assur groups into Assur groups, so that the force analysis problem of metamorphic mechanisms is converted into the force analysis problems of conventional planar mechanisms. The constraint force change rules and values of metamorphic joints are obtained by the proposed method, and the constraint force analysis equations of revolute metamorphic joints in augmented Assur group RRRR and prismatic metamorphic joints in augmented Assur group RRPR are deduced. The constraint force analysis is illustrated by the constrained spring force design of paper folding metamorphic mechanism, and its metamorphic working process is controlled by the spring force and geometric constraints of metamorphic joints. The results of spring force show that developped design method and approach are feasible and practical. By transforming augmented Assur groups into Assur groups, a new method for the constraint force analysis of metamorphic joints is proposed firstly to provide the basis for dynamic analysis of metamorphic mechanism.

A review of graph theory application research in gears

Graph theory has been applied to gear train analysis and synthesis for many years, and it is an effective and systematic modeling approach in the design process of gear transmission. Based on more than 100 references listed in this paper, a review about the graph-based method for kinematic and static force analysis, power flow, and mechanical efficiency computation is presented. The method is based on the concept of fundamental circuit corresponding to a basic epicyclic gear train. A 1-dof epicyclic gear train and a two-stage planetary gear train are used to illustrate the application of this method. Besides, isomorphism identification in the synthesis process and enumeration of 1-dof epicyclic gear train graphs are surveyed particularly. Also, the computerized methods for detection of redundant gears and degenerate structures in epicyclic gear trains are reviewed, respectively.

Совместный метод кинематического и силового анализа сложных механических систем

Совместный метод кинематического и силового анализа сложных механических систем

A method for force analysis of the overconstrained lower mobility parallel mechanism

A novel method for force analysis of the overconstrained lower mobility parallel mechanisms (LMPM) is proposed. Firstly, definitions of the constraint wrenches and overconstraint wrenches are put forward. Then, overconstrained LMPMs are classified into two classes based on characteristic of the elastic deformations generated at the end of the supporting limbs, which are limb stiffness decoupled overconstrained LMPM and limb stiffness coupled overconstrained LMPM, respectively. Corresponding to the limb stiffness decoupled and coupled overconstrained LMPMs, stiffness matrix of the supporting limb's overconstraint wrenches and constraint wrenches are introduced and defined respectively. Next, taking the link's spatial composite elastic deformations into account, the stiffness matrix of the supporting limb's overconstraint wrenches or constraint wrenches is established, and general analytical expression for the solution of each supporting limb's overconstraint wrenches or constraint wrenches is derived. Furthermore, the internal relation between the constraint wrenches and the actual joint reactions is discussed. Finally, based on Adams simulation software, a method to set up the force simulation model of the overconstrained LMPM is put forward, and the simulation results and the theoretical calculation ones are basically consistent, which effectively verifies the correctness of the proposed method for force analysis of the overconstrained LMPM.

Method for Force Analysis of the Overconstrained Parallel Mechanism Considering the Link’s Spatial Composite Elastic Deformations

Method for Force Analysis of the Overconstrained Parallel Mechanism Considering the Link’s Spatial Composite Elastic Deformations

Investigation of Carbon Fiber Wetting Process by Wilhelmy Method and Force Analysis Method

Carbon fiber dynamic wetting measurement system is established based on DCAT 21 tensiometer. The same carbon fiber wetting property are measured by Wilhelmy method and based on force analysis method, which obtained the contact angle is 78.15°and 81°respectively. The results show that complicated preparation exists on the Wilhelmy method, as well as soft fiber is not suitable by this process. However, force analysis method can solve this problem, measuring speed of this method is quickly and applicable. Keywords: contact angle; Wilhelmy method; carbon fiber; wetting; force analysis method

Cogging Force Reduction of Permanent Magnet Single-Phase Linear Generator Applied in Wave Energy Conversion System

This paper proposes a permanent magnet single-phase linear generator (PMSPLG) with Halbach PM Array applied in wave energy conversion system and illustrates how the parameter changes in the geometry of permanent magnet and slot affect the cogging force of the generator. Moreover, the cogging force analysis method in PMSPLG is improved based on the cogging torque analysis method of permanent magnet synchronous rotation machine. Due to experiment results of prototype concordant with the analysis results of the analytical method and the finite-element method, the proposed model and analytical method are correct and effective.

The Research Nonlinear Mechanics for Non-Backlash Output Mechanism of Precision Ball Planetary Drive

Precision ball planetary drive is mainly composed of non-backlash cycloid ball reduction speed mechanism and non-backlash ball ring groove equal speed output mechanism (NBRGEO mechanism or called W mechanism). The three-dimension contact force is analyzed. The nonlinear mechanics model of NBRGEO mechanism was established. The formulas of contact force and stress were deduced. A numerical example is intended to illustrate the presented method of contact force analysis by using of computer program. Therefore, the contact force and stress distributing characteristics of NBRGEO mechanism is acquired. The research results offer theoretical basis for the design of NBRGEO mechanism of the precision ball planetary drive and the research of other precision planetary transmission.

ロボットマニピュレーションにおける接触力の剛体モデルに基づく解析について

This paper discusses points of issue on static analysis of indeterminate contact forces raised by Omata. In summary, 1) Rigid-body-based analysis of static contact forces may have an advantage over elastic-contact-based analysis, which is physically more accurate, from an engineering viewpoint. 2) The elastic-contact-based method for contact force analysis by Rimon et al. is applicable only when preload contact forces are known and therefore it cannot always substitute for the conventional rigid-body model with Coulomb friction. 3) Virtual slidings and their combinations used in rigid-body-based analysis by the authors correspond to actual physical phenomena of contact forces.

Finite Element Analysis for Cycloid Gear and pin Teeth of FA Cycloid Drive Based on ANSYS

In order to validate the force analysis between cycloid gear and pin wheel, the paper built the contact FEM model of between cycloid gear and pin teeth, analyzed statically three-dimensional contact analysis for them and get their contact state. The calculation results coincided with the force analysis method and proved the correctness of the stress analysis theory.

Stability Analysis of Duchuanbian Collapse

Duchuanbian collapse is located inside Micangshan avenue in Nanjiang county, Sichuan province, consisting of 6 dangerous rock bands. It is in a basically stable state overall now, with partial area in a semi-stable or unstable state. Qualitative analysis is carried out in stereographic projection method taking 1st dangerous rock band of Duchuanbian collapse for example, so as to understand the structure feature of slope rock mass, and judge it may occur collapse in falling type.And then static force analysis method is used for quantitative calculations, thus determining that 1st dangerous rock band is in semi-stable state under natural condition, and it may occur collapse under action of torrential rain, earthquake and other unfavorable factors. Therefor, it requires to take reasonable measures for comprehensive treatment.

Force Analysis Methods and Experimental Research on Double-Curved Arch Bridge

Research on section conversion of main arch ring and computation theory of lateral distribution in double-curved arch bridge. Through analyzing load experimental data of ShuiWen bridge, it demonstrates that the plane system finite element method is simple and practical compared to three-dimensional physical model in double-curved arch bridge computation, and the accuracy meets the design requirement .To double-curved arch bridge with spandrel arch, it can put loads distribute averagely on main arch ring to compute, the result is security without regard to joint action of above arch structure

The Simulation Analysis of Ball Screw Pair Contact Characteristics Based on ADAMS

In the mechanical motion ,wear always exists. Different contact stress will lead to different wear characteristics. This paper proposes a method for contact force analysis. According to the Hertz contact theory and in impact function model the dynamic simulation mold is set up. Taking the recognition system with binocular visual angle ball screw pair for example, based on ADAMS and virtual prototype technology, establishment of ball screw ADAMS model and theoretically analyse the impact of ball screw pair contact force causes . In view of the main factor, get the ball contact force distribution. Analysis shows that reasonable selection of ball screw parameters can reduce the ball contact force extreme and inhibit ball screw wear ,which has the reference significance. At the same time, the research of virtual prototyping technology application provides an effective method in new product development.

Kinematic and force analysis of universal multiple differential mechanism of automatic gearboxes

In the article there are presented structural and kinematic schemes and the design of the module of automatic gearboxes on the basis of universal multiple differential mechanism, designed by the authors. There is also considered the method of kinematic and force analysis.

Numerical simulation of the hydrodynamics of self-propelled fish swimming

Based on a novel method of force analysis, the thrust anddrag forces of self-propelled fish are redefined, and the difficulty indistinguish the thrust and drag in fish swimming is overcome. Then, anadaptive ghost-cell immersed boundary method is used to simulate the 2Dself-propelled carangiform swimming. Simulation cases are carried out forReynolds number in the rang of 309 \le Re \le 14581 (viscous flow) andRe=\infty (inviscid flow). The results show that: (1) The Strouhal numberdecreases with increasing the Reynolds number. If the Reynolds number tendstowards infinite, the Strouhal number approaches 0.25; (2) For all Reynoldsnumber, the main part of the thrust is the pressure component. The viscouspart of the drag is larger than the pressure part when Re 3000; (3) The thrust efficiencyincreases with increasing the Reynolds number and the maximum efficiency isabout 70%. The result show that the carangiform swimming rule suit thehigh Reynolds situation.

GEOMETRICALLY NONLINEAR ANALYSIS OF STEEL STORAGE RACKS SUBMITTED TO EARTHQUAKE LOADING

Steel storage racks are light and flexible structures. When submitted to earthquake loading, they can exhibit very large transverse displacements and are thus prone to significant consequences of second-order geometrical effects. In the context of the drafting of European recommendations for the design of steel pallet racks for their seismic resistance, this paper presents a parameter study comparing the various methods commonly used in practice for analyzing the seismic structural behavior of racks (i.e. "modal response spectrum analysis" and "lateral force method analysis") as well as the different ways to account for geometrically nonlinear effects in these conventional methods of analysis in the case of structures designed for low ductility.

Seismic response of structures with coupled vertical stiffness–strength irregularities

AbstractSeveral seismic design codes around the world restrict the use of theit Equivalent Lateral Force analysis method to structures satisfying structural regularity limits. These regularity limits are based on engineering judgement and lack quantitative justification. One common irregularity is that of a change in vertical stiffness over the building height. This stiffness irregularity is almost always associated with a change in vertical strength over the building height. For this reason, the effect of various realistic combinations of stiffness–strength irregularity in shear‐type buildings is evaluated to quantify regularity limits.Structures analysed had 3, 5, 9 and 15 storeys, and the floor mass at all the levels were kept the same. Both regular and irregular structures were designed in accordance with the Equivalent Lateral Force procedure to produce the same engineering demand parameter. Structural ductility factors of 1, 2, 3, 4 and 6, and target (design) interstorey drift ratios ranging between 0.5 and 3%, were used in this study. The irregular structures were created by modifying specific storey lateral stiffnesses from that of the regular structure. Strengths at these storeys were also modified to ensure realistic relationships between stiffness and strength. The modified structures were then redesigned until the target interstorey drift ratio was achieved at the critical storey. Inelastic dynamic time‐history analysis was conducted to compare the maximum interstorey drift ratio demands of the regular and irregular structures. Simple equations were developed to estimate possible variations in demand due to vertical stiffness–strength irregularity applied at critical locations in structures. Copyright © 2011 John Wiley & Sons, Ltd.