A Three-Dimensional Multibody Model of a Full Suspension Mountain Bike

2014 ◽  
pp. 133-142 ◽  
Author(s):  
B. Corves ◽  
J. Breuer ◽  
F. Schoeler ◽  
P. Ingenlath
Keyword(s):  
Three Dimensional ◽  
Mountain Bike ◽  
Multibody Model

Efficient Simulation of Gear Contacts Including Transient Elastohydrodynamic Effects

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Peter Fietkau ◽  
Bernd Bertsche
Keyword(s):  
Three Dimensional ◽  
Direct Determination ◽  
Simulation Method ◽  
Elastic Half Space ◽  
Operating Conditions ◽  
Multibody Simulation ◽  
Multibody Model ◽  
Gear Contact ◽  
Oil Films ◽  
Lubrication Conditions

This paper describes an efficient transient elastohydrodynamic simulation method for gear contacts. The model uses oil films and elastic deformations directly in the multibody simulation, and is based on the Reynolds equation including squeeze and wedge terms as well as an elastic half-space. Two transient solutions to this problem, an analytical and a numerical one, were developed. The analytical solution is accomplished using assumptions for the gap shape and the pressure in the middle of the gap. The numerical problem is solved using multilevel multi-integration algorithms. With this approach, tooth impacts during gear rattling as well as highly loaded power-transmitting gear contacts can be investigated and lubrication conditions like gap heights or type of friction may be determined. The method was implemented in the multibody simulation environment SIMPACK. Therefore it is easy to transfer the developed element to other models and use it for a multitude of different engineering problems. A detailed three-dimensional elastic multibody model of an experimental transmission is used to validate the developed method. Important values of the gear contact like normal and tangential forces, proportion of dry friction, and minimum gap heights are calculated and studied for different conditions. In addition, pressure distributions on tooth flanks as well as gap forms are determined based on the numerical solution method. Finally, the simulation approach is validated with measurements and shows good consistency. The simulation model is therefore capable of predicting transient gear contact under different operating conditions such as load vibrations or gear rattling. Simulations of complete transmissions are possible and therefore a direct determination of transmission vibration behavior and structure-borne noise as well as of forces and lubrication conditions can be done.

A generalized multibody model for inversion of magnetic anomalies

Geophysics ◽  
1980 ◽  
Vol 45 (2) ◽  
pp. 255-270 ◽  
Author(s):  
B. K. Bhattacharyya
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Magnetization Vector ◽  
Critical Dimension ◽  
Magnetic Anomalies ◽  
Field Vector ◽  
Magnetic Survey ◽  
Multibody Model ◽  
Anomalous Field ◽  
Rectangular Block

The height of the observation surface above a magnetized region primarily determines the critical dimension of the smallest inhomogeneity in magnetization that can be resolved from magnetic survey data. When a rectangular block is smaller in size than this critical dimension, it appears homogeneously magnetized in the observed magnetic field. This consideration leads to the selection of a unit rectangular block of suitable dimensions with homogeneous magnetization. The magnetized region creating the anomalous field values in the area of observation can, therefore, be broken up into several blocks having different magnetizations, each block being equal in size and uniformly magnetized. The iterative method described here assumes initially that the anomalous field values are caused by a three‐dimensional (3-D) distribution of magnetized rectangular blocks. The optimum orientation of these blocks with respect to geographic north is then determined. This orientation is particularly insensitive to adjustments in the dimensions of the blocks. The top and bottom surfaces of each of the blocks in one or more layers are adjusted in a least‐squares sense to minimize the difference between observed and calculated field values. A method is also described for constraining the magnetization vector of each block to lie within a specified angle of the normal or reversed direction of the geomagnetic field vector. The procedure for analysis of data can also be extended to the case of anomalies over a draped surface. At the conclusion of the iterations, a 3-D distribution of magnetization is generated to delineate the magnetized region responsible for the observed anomalous magnetic field. Examples including model and aeromagnetic data are provided to demonstrate the usefulness of a generalized multibody model for inversion of magnetic anomalies.

scholarly journals How Compliance of Surfaces Affects Ankle Moment and Stiffness Regulation During Walking

2021 ◽  
Vol 9 ◽  
Author(s):  
Kaifan Xie ◽  
Yueling Lyu ◽  
Xianyi Zhang ◽  
Rong Song
Keyword(s):  
Model Development ◽  
Three Dimensional ◽  
Underlying Mechanism ◽  
Surface Design ◽  
Ankle Moment ◽  
Multibody Model ◽  
Gait Biomechanics ◽  
Ankle Stiffness ◽  
Reaction Forces ◽  
Different Levels

Humans can regulate ankle moment and stiffness to cope with various surfaces during walking, while the effect of surfaces compliance on ankle moment and stiffness regulations remains unclear. In order to find the underlying mechanism, ten healthy subjects were recruited to walk across surfaces with different levels of compliance. Electromyography (EMG), ground reaction forces (GRFs), and three-dimensional reflective marker trajectories were recorded synchronously. Ankle moment and stiffness were estimated using an EMG-driven musculoskeletal model. Our results showed that the compliance of surfaces can affect both ankle moment and stiffness regulations during walking. When the compliance of surfaces increased, the ankle moment increased to prevent lower limb collapse and the ankle stiffness increased to maintain stability during the mid-stance phase of gait. Our work improved the understanding of gait biomechanics and might be instructive to sports surface design and passive multibody model development.

scholarly journals A Three-Dimensional Parametric Biomechanical Rider Model for Multibody Applications

2020 ◽  
Vol 10 (13) ◽  
pp. 4509
Author(s):  
Matteo Bova ◽  
Matteo Massaro ◽  
Nicola Petrone
Keyword(s):  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Experimental Comparison ◽  
Minor Effect ◽  
Data Sets ◽  
Data Set ◽  
Multibody Model ◽  
Inertial Parameters ◽  
A Minor

Bicycles and motorcycles are characterized by large rider-to-vehicle mass ratios, thus making estimation of the rider’s inertia especially relevant. The total inertia can be derived from the body segment inertial properties (BSIP) which, in turn, can be obtained from the prediction/regression formulas available in the literature. Therefore, a parametric multibody three-dimensional rider model is devised, where the four most-used BSIP formulas (herein named Dempster, Reynolds-NASA, Zatsiorsky–DeLeva, and McConville–Young–Dumas, after their authors) are implemented. After an experimental comparison, the effects of the main posture parameters (i.e., torso inclination, knee distance, elbow distance, and rider height) are analyzed in three riding conditions (sport, touring, and scooter). It is found that the elbow distance has a minor effect on the location of the center of mass and moments of inertia, while the effect of the knee distance is on the same order magnitude as changing the BSIP data set. Torso inclination and rider height are the most relevant parameters. Tables with the coefficients necessary to populate the three-dimensional rider model with the four data sets considered are given. Typical inertial parameters of the whole rider are also given, as a reference for those not willing to implement the full multibody model.

An improved three-dimensional multibody model of the human spine for vibrational investigations

2015 ◽  
Vol 36 (4) ◽  
pp. 363-375 ◽  
Author(s):  
Pier Paolo Valentini ◽  
Ettore Pennestrì
Keyword(s):  
Three Dimensional ◽  
Multibody Model ◽  
Human Spine

Dynamics and modeling of rocket towed net system

2016 ◽  
Vol 232 (1) ◽  
pp. 185-197 ◽  
Author(s):  
Shen Jian ◽  
Han Feng ◽  
Chen Fang ◽  
Zhou Qiao ◽  
Pavel M Trivailo
Keyword(s):  
Dynamical Behavior ◽  
Three Dimensional ◽  
Experimental Results ◽  
Future Research ◽  
Three Dimensional Model ◽  
Lumped Mass ◽  
Mass Model ◽  
Multibody Model ◽  
Dynamical Parameters ◽  
Rigid Multibody

In order to study the complex dynamical behavior of the rocket towed net system, a three-dimensional model consisting of a rigid rocket model and a lumped mass net model is built based on the aerodynamics theory. The rocket towed net system model is solved by the fourth-order Runge–Kutta method in simulation. Simulation and experimental results show that the accuracies of rocket towed net system expanding distance were about 90% of the system length. With the comparison of simulation, a rigid multibody model and experimental results in rocket mass center trajectory, velocity, and pitch angle, the dynamical characteristics of rocket towed net system have been basically studied. It illustrates that the lumped mass model simulates the real rocket towed net system flying test better than the rigid multibody model. It also shows that the dynamical parameters of rocket towed net system flight have an impact on the system in the whole flying process. Constitutive model of flexible net mesh-belts can be considered in the future research studies.

A Simple Mechanical Model for Simulating Cross-Country Skiing Propulsive Force

2015 ◽  
Author(s):  
John Bruzzo ◽  
A. L. Schwab ◽  
Aki Mikkola ◽  
Antti Valkeapää ◽  
Olli Ohtonen ◽  
...  
Keyword(s):  
Motion Capture ◽  
Incline Plane ◽  
Three Dimensional ◽  
Motion Capture System ◽  
Multibody Model ◽  
Multibody Dynamic ◽  
Cross Country Skiing ◽  
Cross Country ◽  
Propulsion Phase ◽  
Resultant Forces

In this paper, a three-dimensional multibody dynamic model of a cross-country skier is developed and presented where a single propulsion phase is modeled to obtain the kinetic parameters involved in the movement. A professional Olympic-level skier performed the skating technique without poles in a ski tunnel under controlled conditions and on an incline plane. Then, with the use of a force acquisition system attached to the ski bindings and a motion capture system set on site, the leg resultant forces and the movement of specific points of the skier’s lower body were acquired. The data obtained from the motion capture system was used as the prescribed kinematic input data in the multibody model and the measured force was used later as a comparison parameter with the results of the simple model. After simulating the technique, the calculated propulsion forces seem to be in agreement with those measured in the field.

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