Simulation Of Mechanical Systems Research Articles

Simulation of Mechanical System with Two Degrees of Freedom with Bond Graphs and MATLAB/Simulink

Abstract The work shows the use of Bond Graph formalism for modeling dynamic systems. As an example a mechanical model of 2 DOF is solved by this approach at the level of its physical behavior. In contrast with the classical method, where the equations for individual components are created first and then the simulation scheme is derived on their basis, the described method uses the reverse procedure.

Simulation of Nonholonomic Mechanical Systems Using Algorithmic Differentiation

AbstractThe purpose of this contribution is to introduce a new approach for simulating mechanical systems with nonholonomic constraints. The technique of algorithmic differentiation is employed together with Hamel’s equations of motion permitting to incorporate the nonholonomic constraints directly instead of generating a system of differential-algebraic equations. To apply the proposed simulation approach, the user only needs to state the kinetic and potential energies, the nonconservative forces, and the nonholonomic constraints of the system to be simulated. The procedure is demonstrated by an illustrating example of a nonholonomic moving robot.

Conceptual Design of Hybrid-Driven Precision Press

In this paper, a novel precision press is proposed, which is to combine the motion of a large constant speed motor with a small servomotor via a two-DOF mechanism, where, the constant speed motor provides main torque and motion requirements, while the servomotor contributes to modulations on this motion. The forward kinematic optimal design, electromechanical system dynamics modeling and simulation of this new mechanical press system have been presented here. The simple analysis of theoretical feasibility of the hybrid-driven press is investigated.

Dynamics Analysis of Gear Mesh of Transmission Based on Virtual Prototype

A commercial transmission provided by enterprise is analyzed in this paper. Its 3D model is established in UG software, its dynamic force and corresponding frequency diagram of constant mesh gear pair is analyzed in coupling mechanical system simulation(ADAMS). According to the result of analysis, the conclusion can provide basis for fatigue property, strength checking, structure optimization of gears and shafts, and noise abatement of global transmission. This method is an additional project for the stability, security of transmission products.

Interactive virtual prototyping of a mechanical system considering the environment effect. Part 2: Simulation quality

Perhaps the three most important issues in numerical simulation of mechanical systems are: (1) how well do the multi-body systems represent a physical system of interest; (2) how efficient is the simulation; and (3) how accurate is the simulation. With the advances in computational mechanics, the efficiency of multi-body simulations is steadily improving. Indeed, analysts are increasingly envisioning real-time simulation. With these improvements in computation and efficiency, the modeling of physical systems is also improving through the ability to have more comprehensive modeling. The issue of accuracy, however, remains. Generally, the complexity of multi-body system dynamics leaves the analyst without firm assurance about the numerical accuracy short of experimental verification or intuitive reasonableness of the results. In the second part of the paper we present some methods and experiments to clarify simulation quality of the basic model described in the first article.

Modeling of MEMS-Based Fuel Cells Using SUGAR and Reliability Calculations

Unified approach for modeling and simulation of microelectro mechanical systems (MEMs) and nano-enabled fuel cells has been proposed. A novel way to approach reliability of MEMS-enabled fuel cells is discussed incorporating recent developments and proposals. We know that reliability modeling and accurate prediction of properties in nano domains remains a major challenge where still theories are still under development. Hence accurate prediction and modeling still remains a challenging area. A direct methanol fuel cell (DMFC) has benefited maximum from progression in MEMS technologies in bringing out advances in its existing framework. The necessity of a porous membrane has been eminent in recent fuel cells, where a comprehensive computation model in this area is still not available. This need for MEMS-based models for porous silicon-based membranes based on nano imprints technology has been met by modeling it in SUGAR-MATLAB environment. MEMS technologies are explored in modeling of tubes, capillary pump, micro channels and other structures which is an emerging area for fuel cells. Finally, the reliability analysis is done to assess their application in real devices. Development of strong reliability theories backed by computational and theoretical proofs can assist in rapid commercialization of such technologies. MEMS enable fuel cells can reduce carbon emissions and provide a sustainable future based on green energy solutions.

Sliding Modes for the Simulation of Mechanical and Electrical Systems Defined by Differential-Algebraic Equations

We offer a technique, motivated by feedback control and specifically sliding mode control, for the simulation of differential-algebraic equations (DAEs) that describe common engineering systems such as constrained multibody mechanical structures and electric networks. Our algorithm exploits the basic results from sliding mode control theory to establish a simulation environment that then requires only the most primitive of numerical solvers. We circumvent the most important requisite for the conventional simulation of DAEs: the calculation of a set of consistent initial conditions. Our algorithm, which relies on the enforcement and occurrence of sliding mode, will ensure that the algebraic equation is satisfied by the dynamic system even for inconsistent initial conditions and for all time thereafter.

Onsager–Machlup action-based path sampling and its combination with replica exchange for diffusive and multiple pathways

For sampling multiple pathways in a rugged energy landscape, we propose a novel action-based path sampling method using the Onsager-Machlup action functional. Inspired by the Fourier-path integral simulation of a quantum mechanical system, a path in Cartesian space is transformed into that in Fourier space, and an overdamped Langevin equation is derived for the Fourier components to achieve a canonical ensemble of the path at a finite temperature. To avoid "path trapping" around an initially guessed path, the path sampling method is further combined with a powerful sampling technique, the replica exchange method. The principle and algorithm of our method is numerically demonstrated for a model two-dimensional system with a bifurcated potential landscape. The results are compared with those of conventional transition path sampling and the equilibrium theory, and the error due to path discretization is also discussed.

Octree-search Kinetic Monte Carlo

We present a Kinetic Monte Carlo (KMC) method based on an octree data representation and search algorithm for the simulation of complex Micro Electro Mechanical Systems (MEMS) structures and, in general, complex, multi-valued surfaces propagating in 3D space. The experimental etch rate distribution for a wet etched spherical sample is correctly described and the propagation of the surface is in good agreement with the experiments for various applications. The algorithm leads to a faster tree-based search, efficient updating and good modeling ability for dynamic surfaces. Speedup factors of 3–4 over similar methods are obtained while the use of memory is reduced by 50–80% with respect to standard practice, with the factor increasing for larger simulations.

A 17th-order Radau IIA method for package RADAU. Applications in mechanical systems

A new Radau IIA code with an order of 17 is programmed for the well-known implicit Runge–Kutta program package RADAU. Several numerical examples are reported in this article to demonstrate the performance and efficiency of the new algorithm. They are real stiff problems obtained from the simulation of mechanical systems.

Port-Based Modeling and Simulation of Mechanical Systems With Rigid and Flexible Links

In this paper, a systematic procedure for the definition of the dynamical model in port-Hamiltonian form of mechanical systems is presented as the result of the power-conserving interconnection of a set of basic components (rigid bodies, flexible links, and kinematic pairs). Since rigid bodies and flexible links are described within the port-Hamiltonian formalism, their interconnection is possible once a proper relation between the power-conjugated port variables is deduced. These relations are the analogous of the Kirchhoff laws of circuit theory. From the analysis of a set of oriented graphs that describe the topology of the mechanism, an automatic procedure for deriving the dynamical model of a mechanical system is illustrated. The final model is a mixed port-Hamiltonian system, because of the presence of a finite-dimensional subsystem (modeling the rigid bodies) and an infinite-dimensional one (describing the flexible links). Besides facilitating the deduction of the dynamical equations, it is shown how the intrinsic modularity of this approach also simplifies the simulation phase.

A new family of constrained redundant parallel manipulators

This paper addresses the description and kinematic analysis of a new family of redundant parallel manipulators. The primary feature of the new family is to have a compact topology consisting of multi-degree of freedom non-identical limbs. In order to simplify the forward position analysis, the motion of the end-effector (platform) is decoupled into translational and rotational components with respect to the base. This kind of topology is in agreement with the parallel manipulator definition of IFToMM—a parallel manipulator “…that controls the motion of its end-effector by means of at least two kinematic chains going from the end effector towards the frame…”. In fact, adding a kinematic pair to a limb of a non-redundant parallel manipulator creates asymmetrical parallel manipulator. Analytical expressions for the forward position, velocity, and acceleration of the parallel manipulators have been obtained and solved for an exemplary 7-DOF redundant parallel manipulator. The numerical results from the analytical expressions are verified by comparing them to the results from a mechanical system simulation software as if a real parallel manipulator is being run to collect the position, velocity, and acceleration data. Finally, based on the velocity formulation, the singularity analysis of the manipulator is also provided.

Uses of New Sensitivity and Dae Solving Methods in SmartMobile for Verified Analysis of Mechanical Systems

Uses of New Sensitivity and Dae Solving Methods in SmartMobile for Verified Analysis of Mechanical SystemsSoftware for modeling and simulation (MSS) of mechanical systems helps to reduce production costs for industry. Usually, such software relies on (possibly erroneous) finite precision arithmetic and does not take into account uncertainty in the input data. The program SmartMobile enhances the existing MSS Mobile with verified techniques to provide a guarantee that the obtained results are correct and measure the influence of data uncertainty. In this paper, we outline the main features and functionalities of SmartMobile. In particular, we focus on its use of newly developed methods for sensitivity analysis and DAE solving for several practically relevant mechanical systems.

5.1.3 Testing Solutions through SysML / UML

AbstractAs systems become increasingly complex and the time to market decreases, systems engineers have to develop novel solutions to testing. The scenario is particularly acute when dealing within the safety critical domain. This paper will seek to highlight how UML and in particular, improvements introduced by SysML can aid the testing process in terms of verification, validation and simulation of software, firmware and mechanical systems. This paper will highlight how UML and SysML constructs can aid testing and is based on many years experience of building and testing systems as well as the experience gained by client companies during consultation. It will highlight on a practical basis how clients have integrated testing into their UML/SysML models to improve their processes and products.

Parameter identification of damping models in multibody dynamic simulation of mechanical systems

To reduce vibration and noise, a damping mechanism is often required in mechanical systems. Many types of dampers are currently used. In this paper, several typical damping models, i.e., structural damping, frictional damping, and viscoelastic damping, are illustrated, and their parameters are identified for multibody dynamic simulation. Linear damping, widely adopted for structural damping, is applied to beam deflection. Quadratic damping including air resistance is applied to plate deflection. To model stick phenomenon in mechanical dampers, a STV (stick-transition velocity) model was first introduced. To identify parameters, an optimization process is applied to the damping parameters. A new MSTV (modified stick-transition velocity) model is proposed for a friction damper. A modified Kelvin–Voight model is suggested for a rubber bushing model used in vehicle dynamics, and its parameters are identified. A modified Bouc–Wen model is also proposed; it includes the hysteretic behavior of an elastomer, and optimized results with parameter identification are compared to test results.

Influence of a shock absorber model on vehicle dynamic simulation

The dynamic simulation of mechanical systems is an essential tool in vehicle design. This work analyses the influence of a shock absorber model on a vehicle's dynamic behaviour by means of a simulation-based model. The real behaviour of a European medium-range car shock absorber has been obtained by means of a test rig. From the damper's real behaviour, three mathematical models were generated, increasing the complexity. An existing full vehicle simulation application (CarSim™) was used for this particular study. The vehicle's behaviour was analysed for typical driving manoeuvres taking into account lateral, vertical, and longitudinal forces and was compared with the results obtained with the different shock absorber models developed. As a result of this paper, it was demonstrated that, in order to obtain results with an acceptable level of accuracy, it is not necessary to rely on extremely complex shock absorber models.

484 離散ハミルトン系に基づくホロノミック力学系の定式化と幾何学的拘束安定化

This paper develops discrete holonomic Hamiltonian systems that is based on the discretization by the Backward Differentiation Formula and with geometric constraint stabilization, which enables one to effectively stabilize constraint violations that appear in numerical simulations of holonomic mechanical systems. We illustrate the validity of the proposed discrete holonomic Hamiltonian systems by an illustrative example of linkage mechanisms in comparison with conventional constraint stabilization methods such as the GGL method and the Baumgarte method.

Preliminary simulation of the GAP mechanical system for oil sands haulage

Kinematic synthesis and dynamic simulation of the Ground Articulating Pipeline (GAP) system has been carried out with Automatic Dynamic Analysis of Mechanical Systems (ADAMS) software. A kinematics model of the GAP mechanism has been built based on the kinematics of machinery. The equations of Newton-Euler dynamics were employed as the computational framework for the dynamic simulation of the system. A virtual prototype has been created and simulated in the ADAMS environment. The simulation has been integrated with real time 3-D system for detailed and responsive interactions with dynamic virtual environments. The results of the kinematics synthesis showed that the GAP system consists of 14 pipe arms and seven master carriages to accommodate a shovel advance of 400 m per week. The results of the dynamic simulation showed that the GAP system meets the operating requirement of each slave master displacement of 60 m with good operating characteristics.

An exact nonlinear hybrid-coordinate formulation for flexible multibody systems

The previous low-order approximate nonlinear formulations succeeded in capturing the stiffening terms, but failed in simulation of mechanical systems with large deformation due to the neglect of the high-order deformation terms. In this paper, a new hybrid-coordinate formulation is proposed, which is suitable for flexible multibody systems with large deformation. On the basis of exact strain-displacement relation, equations of motion for flexible multibody system are derived by using virtual work principle. A matrix separation method is put forward to improve the efficiency of the calculation. Agreement of the present results with those obtained by absolute nodal coordinate formulation verifies the correctness of the proposed formulation. Furthermore, the present results are compared with those obtained by use of the linear model and the low-order approximate nonlinear model to show the suitability of the proposed models.

MontePython: Implementing Quantum Monte Carlo using Python

We present a cross-language C++/Python program for simulations of quantum mechanical systems with the use of Quantum Monte Carlo (QMC) methods. We describe a system for which to apply QMC, the algorithms of variational Monte Carlo and diffusion Monte Carlo and we describe how to implement theses methods in pure C++ and C++/Python. Furthermore we check the efficiency of the implementations in serial and parallel cases to show that the overhead using Python can be negligible. Program summary Program title: MontePython Catalogue identifier: ADZP_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADZP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 49 519 No. of bytes in distributed program, including test data, etc.: 114 484 Distribution format: tar.gz Programming language: C++, Python Computer: PC, IBM RS6000/320, HP, ALPHA Operating system: LINUX Has the code been vectorised or parallelized?: Yes, parallelized with MPI Number of processors used: 1–96 RAM: Depends on physical system to be simulated Classification: 7.6; 16.1 Nature of problem: Investigating ab initio quantum mechanical systems, specifically Bose–Einstein condensation in dilute gases of 87Rb Solution method: Quantum Monte Carlo Running time: 225 min with 20 particles (with 4800 walkers moved in 1750 time steps) on 1 AMD Opteron TM Processor 2218 processor; Production run for, e.g., 200 particles takes around 24 hours on 32 such processors.