DOI•
Analysis of ride comfort of a continuous tracked bogie system with variable configuration
19 Jun 2020-Vol. 234, Iss: 14, pp 3429-3439
TL;DR: In this study, the effect of change in height of a so-called variable configuration of a continuous tracked bogie system on ride comfort performance is investigated.
Abstract: In this study, the effect of change in height of a so-called variable configuration of a continuous tracked bogie system on ride comfort performance is investigated To this end, constraint equatio
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01 Nov 1975
TL;DR: In this article, the evolution of the standard is discussed and its application to vehicle ride quality is considered in the context of the safety, efficiency and comfort of crew and passengers, particularly the difficulties of first defining comfort and then postulating appropriate levels.
Abstract: The evolution of the standard, which is aimed at promoting research and production of more data, and providing some design guidance, is outlined and its contents summarized. Some of the assumptions and information on which it is based are analyzed. Its application to vehicle ride quality is considered in the context of the safety, efficiency and comfort of crew and passengers. The importance of establishing the precise criteria against which vibration limits are required is underlined, particularly the difficulties of first defining comfort and then postulating appropriate levels. Some current and future work related to improving the standard is outlined and additional suggestions offered.
626 citations
TL;DR: In this article, the authors developed compliant track link models and investigated the use of these models in the dynamic analysis of high-speed, high-mobility tracked vehicles, where the compliant elements used in this investigation to describe the track joints are measured experimentally.
Abstract: Several modelling methods have recently been developed for the dynamic analysis of low-speed tracked vehicles. These methods were used to demonstrate the significant effect of the force of the interaction between the track links and vehicle components, even when low speeds are considered. It is the objective of this investigation to develop compliant track link models and investigate the use of these models in the dynamic analysis of high-speed, high-mobility tracked vehicles. There are two major difficulties encountered in developing the compliant track models discussed in this paper. The first is due to the fact that the integration step size must be kept small in order to maintain the numerical stability of the solution. This solution includes high oscillatory signals resulting from the impulsive contact forces and the use of stiff compliant elements to represent the joints between the track links. The characteristics of the compliant elements used in this investigation to describe the track joints are measured experimentally. A numerical integration method having a relatively large stability region is employed in order to maintain the solution accuracy, and a variable step size integration algorithm is used in order to improve the efficiency. The second difficulty encountered in this investigation is due to the large number of the system equations of motion of the three-dimensional multibody tracked vehicle model. The dimensionality problem is solved by decoupling the equations of motion of the chassis subsystem and the track subsystems. Recursive methods are used to obtain a minimum set of equations for the chassis subsystem. Several simulations scenarios including an accelerated motion, high-speed motion, braking, and turning motion of the high-mobility vehicle are tested in order to demonstrate the effectiveness and validity of the methods proposed in this investigation. Copyright © 2000 John Wiley & Sons, Ltd.
60 citations
TL;DR: In this paper, the authors developed a computer aided analysis procedure for the dynamic simulation of large-scale tracked vehicles, where the track is considered as a closed kinematic chain that consists of rigid bodies connected by revolute joints.
Abstract: It is known that when two springs are connected in series, the stiffness coefficient of an equivalent system that consists of one spring is less than the stiffness coefficients of the original springs. Experimental observations indicate that this fact can be very useful in determining the overall vibration characteristics of tracked vehicles. This simple fact is used in this investigation to develop a computer aided analysis procedure for the dynamic simulation of large-scale tracked vehicles. The track is considered as a closed kinematic chain that consists of rigid bodies connected by revolute joints. The contacts between the track links and the rollers, the sprocket, and the idler are represented by non-linear continuous force models. The stiffness and damping coefficients in these contact force models are determined by studying the viberation characteristics of the tracked vehicle. The tooth of the sprocket is defined using three surfaces. These are the left, the bottom, and the fight surfaces. Three successive transformations are used to define the contact kinematic relationships between the sprocket teeth and the pins of the track links. The equations of motions of the vehicle are formulated using the Lagrangian approach. Non-linear constraint equations that describe mechanical joints and specified motion trajectories in the system are adjoined to the differential equations of motion using the technique of Lagrange multipliers. The resulting mixed system of differential and algebraic equations is solved numerically using a direct numerical integration method. A Newton–Raphson algorithm is used to check on the violations in the kinematic constraints. The results presented in this paper are obtained using a 54 body planer tracked vehicle in which the track consists of 42 rigid links connected by revolute joints.
34 citations
TL;DR: In this article, the authors focus on the dynamic formulation of mechanical joints using different approaches that lead to different models with different numbers of degrees of freedom, including the ideal, compliant discrete element, and compliant continuum-based joint models.
Abstract: This paper is focused on the dynamic formulation of mechanical joints using different approaches that lead to different models with different numbers of degrees of freedom. Some of these formulations allow for capturing the joint deformations using a discrete elastic model while the others are continuum-based and capture joint deformation modes that cannot be captured using the discrete elastic joint models. Specifically, three types of joint formulations are considered in this investigation; the ideal, compliant discrete element, and compliant continuum-based joint models. The ideal joint formulation, which does not allow for deformation degrees of freedom in the case of rigid body or small deformation analysis, requires introducing a set of algebraic constraint equations that can be handled in computational multibody system (MBS) algorithms using two fundamentally different approaches: constrained dynamics approach and penalty method. When the constrained dynamics approach is used, the constraint equations must be satisfied at the position, velocity, and acceleration levels. The penalty method, on the other hand, ensures that the algebraic equations are satisfied at the position level only. In the compliant discrete element joint formulation, no constraint conditions are used; instead the connectivity conditions between bodies are enforced using forces that can be defined in their most general form in MBS algorithms using bushing elements that allow for the definition of general nonlinear forces and moments. The new compliant continuum-based joint formulation, which is based on the finite element (FE) absolute nodal coordinate formulation (ANCF), has several advantages: (1) It captures modes of joint deformations that cannot be captured using the compliant discrete joint models; (2) It leads to linear connectivity conditions, thereby allowing for the elimination of the dependent variables at a preprocessing stage; (3) It leads to a constant inertia matrix in the case of chain like structure; and (4) It automatically captures the deformation of the bodies using distributed inertia and elasticity. The formulations of these three different joint models are compared in order to shed light on the fundamental differences between them. Numerical results of a detailed tracked vehicle model are presented in order to demonstrate the implementation of some of the formulations discussed in this investigation.
24 citations
TL;DR: In this article, a track-wheel-terrain interaction model is presented, which can be used as a "force" super-element in a multibody dynamics code for dynamic simulation of tracked vehicles.
Abstract: A track-wheel-terrain interaction model is presented in this paper, which can be used as a “force” super-element in a multibody dynamics code for dynamic simulation of tracked vehicles. This model employs a nonlinear finite element representation for the track segment that is in contact with the terrain and roadwheels, which can be used to simulate two different track systems, namely a continuous rubber band track and a multi-pitched metallic track, provided the finite element mesh in the track model is properly defined. The new track model accounts for the tension variations along the track (due to the non-uniformly distributed normal pressure and traction), track extensibility, and geometrically large (nonlinear) track deflections. A new solution algorithm is then proposed that includes an adaptive meshing method for representing track movement during the simulation for the multi-pitch tracks. Doing so produces a track model that captures high-frequency content of the track-wheel-terrain interaction, and it can more accurately describe the mechanics of a multi-pitch track as the vehicle negotiates rough terrain. The resulting track-wheel-terrain model combines approximate and known constitutive laws for terrain response with the new track representation, which allows the computation of the normal and shear forces, as well as the passage frequency, at the track-terrain interface. The track model and solution algorithm are further illustrated in this paper using a simple two-wheel system model and a full vehicle model of an M1A1 tank.
21 citations