Numerical Simulation of Two-Part Underwater Towing System: A Lumped Mass-Spring System Approach

2007 ◽  
Author(s):  
P. P. Lalu
Keyword(s):  
System Approach ◽  
Two Dimensional ◽  
Lumped Mass ◽  
System A ◽  
Submerged Body ◽  
Induced Motion ◽  
Spring System ◽  
Experimental Values ◽  
Mass Spring ◽  
Wave Induced

The altitude and position of a submerged body being towed by a vessel is affected by wave induced motion of the latter. To reduce this disturbance, a two-part towing system is used. In this study a two-dimensional dynamic model of the two-part underwater towing system is described. Numerical modeling of the problem was attempted. The finite difference algorithm was used to formulate the problem. A lumped mass-spring system was used for modeling the cable. The formulation for the towed body was based on Kirchhoff’s equations for motion of a rigid body. For the demonstration of the model, a numerical example of the tow-ship traveling in a wave field is described. Subsequently, response of the towed body was simulated and is compared with the experimental values obtained from the literature.

An Effective Method for Modeling Stiction in Multibody Dynamic Systems

1996 ◽  
Vol 118 (1) ◽  
pp. 172-176 ◽  
Author(s):  
R. G. Synnestvedt
Keyword(s):  
Complex Systems ◽  
Dynamic Systems ◽  
Degrees Of Freedom ◽  
Dynamic Equations ◽  
Stick Slip ◽  
System A ◽  
Multibody Dynamic ◽  
Model Dynamics ◽  
Spring System ◽  
Mass Spring

This paper presents an effective method for developing dynamic equations which realistically model dynamics of multibody mechanical systems with stiction, or stick-slip friction. This method is used in three examples—a mass-spring system, a top, and a robot linkage—to illustrate the facility with which the method is implemented. The method dynamically partitions sets of dynamic equations to model a system through discontinuities, changes in degrees of freedom and changes in states. Comparisons of this method with others is presented for simple and complex systems.

Compression simulations of plant tissue in 3D using a mass-spring system approach and discrete element method

Soft Matter ◽  
2017 ◽  
Vol 13 (40) ◽  
pp. 7318-7331 ◽  
Author(s):  
Piotr M. Pieczywek ◽  
Artur Zdunek
Keyword(s):  
Discrete Element Method ◽  
Hybrid Model ◽  
Plant Tissue ◽  
System Approach ◽  
Discrete Element ◽  
Cellular Structures ◽  
Spring System ◽  
Mass Spring ◽  
System Methodology ◽  
Element Method

A hybrid model based on a mass-spring system methodology coupled with the discrete element method (DEM) was implemented to simulate the deformation of cellular structures in 3D.

Dynamic Analysis on the H-Type Stage Using Largrange Method

2012 ◽  
Vol 542-543 ◽  
pp. 663-666
Author(s):  
Kyoungchon Kim ◽  
Dae Gab Gweon ◽  
Dong Pyo Hong ◽  
Byoungkuk Lee
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Modeling ◽  
Dynamic Performance ◽  
Settling Time ◽  
Positioning System ◽  
Precision Positioning ◽  
Lumped Mass ◽  
Lagrange Method ◽  
Spring System ◽  
Mass Spring

Dynamic performance in the H-type stage as precision positioning system is important specification to guarantee precise accuracy. As the range of the H-type stage has increased, the dynamic performance affects the settling time of the H-type stage. This article concentrates analysis of the dynamic modeling of the H-type stage with rotational flexure joint. The dynamic modeling of the H-type stage was analyzed using Lagrange method assumed as lumped mass-spring system. The dynamic modeling of the H-type stage was verified by the experiment.

Cableless Magnetic Actuator Capable of High-Speed Movement in Pipe by New Type Propulsion Module

2012 ◽  
Vol 452-453 ◽  
pp. 1252-1256 ◽  
Author(s):  
Tomohiro Izumikawa ◽  
Hiroyuki Yaguchi
Keyword(s):  
High Speed ◽  
Resonance Energy ◽  
Magnetic Actuator ◽  
System A ◽  
New Type ◽  
Spring System ◽  
Inspection And Maintenance ◽  
Mass Spring ◽  
Button Batteries ◽  
Very High

The present paper proposes a novel cableless magnetic actuator that exhibits a very high thrusting force and is capable of high speed locomotion in a thin pipe by using new type propulsion module. The magnetic actuator is moved according to the vibration amplitude and elastic energy of a mass-spring system due to mechanical resonance energy. The proposed actuator contains an electrical inverter that directly transforms DC from button batteries into AC. The electrical DC-AC inverter incorporates a mass-spring system, a reed switch and a curved permanent magnet that switches under an electromagnetic force. Experimental results indicate that the proposed actuator is able to move upward at a speed of 51 mm/s by the power provided by 8 button batteries when pulling a 10 g load mass. This cableless magnetic actuator has several possible applications, including small pipe inspection and maintenance.

EFFECT OF MEMORY AND REINFORCEMENT ON THE PROPAGATION AND MORPHOLOGY OF FRACTURE IN A TWO-DIMENSIONAL MASS-SPRING SYSTEM

2009 ◽  
Vol 20 (07) ◽  
pp. 1049-1062 ◽  
Author(s):  
GEORGE ALLAN ESLETA ◽  
CHRISTOPHER MONTEROLA
Keyword(s):  
Power Law ◽  
Damage Accumulation ◽  
Stress Amplitude ◽  
Two Dimensional ◽  
Power Law Distribution ◽  
Deformation History ◽  
Stress Memory ◽  
Structural Reinforcement ◽  
Spring System ◽  
Mass Spring

We investigate the interplay of damage accumulation and structural reinforcement in the fatigue failure of a two-dimensional mass-spring system. Damage accumulation is captured in the model such that the damage of a spring at a certain time depends on its entire deformation history. Structural reinforcement, on the other hand, is implemented by increasing the breaking thresholds of the springs [Esleta and Monterola, Comp. Phys. Comm. 20081]. We demonstrate that consistent with known empirical laws, in the presence of memory, the lifetime tf of the system subjected to a stress amplitude σ0 is a power law [Formula: see text]. As damage accumulation memory f0 is incorporated into the system, the transition from non-power law (f0 = 0, no memory) to power law distribution is observed. Preservation of the power law behavior (equal value of γ) is guaranteed even when the system's lifetime is prolonged through static reinforcement. Finally, our model demonstrates that strengthening the stress memory of spring elements leads to more scattered crack patterns, a result that agrees phenomenologically with existing experiments.

The Windup Phenomenon and Anti-windup Illustrated

2011 ◽  
Author(s):  
Luca Zaccarian ◽  
Andrew R. Teel
Keyword(s):  
Disturbance Rejection ◽  
Feedback Loop ◽  
Robot Manipulator ◽  
Input Saturation ◽  
Positioning System ◽  
System A ◽  
Highly Oscillatory ◽  
Oscillatory Response ◽  
Spring System ◽  
Mass Spring

This chapter uses examples where windup occurs to motivate anti-windup synthesis. In particular, it discusses a SISO academic example, a MIMO academic example, the longitudinal dynamics of an F8 aircraft, a servo-positioning system, the damped mass-spring system, the experimental spring-gantry system, a robot manipulator, and a disturbance rejection problem. The examples illustrate the windup phenomenon, which may arise due to input saturation in a feedback loop, and the capabilities of anti-windup synthesis in mitigating the windup phenomenon. They show that windup can manifest itself as a sluggish response, a highly oscillatory response, or a diverging response. In each example, alternatives to anti-windup synthesis include investing in actuators with more capabilities, or redesigning the controller from scratch to account for input saturation directly. These strategies should be considered when the control system's actuators are continuously trying to act beyond their limits.

scholarly journals Gas-Induced Motion of a Piston in a Vibrated Liquid-Filled Housing

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
John R. Torczynski ◽  
Timothy J. O'Hern ◽  
Jonathan R. Clausen ◽  
Timothy P. Koehler
Keyword(s):  
Nonlinear Damping ◽  
Spring Model ◽  
Piston Motion ◽  
Strong Resonance ◽  
Drift Model ◽  
System A ◽  
Spring Suspension ◽  
Induced Motion ◽  
Spring System ◽  
Piston Position

Models and experiments are developed to investigate how a small amount of gas can cause large rectified motion of a piston in a vibrated liquid-filled housing when piston drag depends on piston position so that damping is nonlinear even for viscous flow. Two bellows serve as surrogates for the upper and lower gas regions maintained by Bjerknes forces. Without the bellows, piston motion is highly damped. With the bellows, the piston, the liquid, and the two bellows move together so that almost no liquid is forced through the gaps between the piston and the housing. This Couette mode has low damping and a strong resonance: the piston and the liquid vibrate against the spring formed by the two bellows (like the pneumatic spring formed by the gas regions). Near this resonance, the piston motion becomes large, and the nonlinear damping produces a large rectified force that pushes the piston downward against its spring suspension. A recently developed model based on quasi-steady Stokes flow is applied to this system. A drift model is developed from the full model and used to determine the equilibrium piston position as a function of vibration amplitude and frequency. Corresponding experiments are performed for two different systems. In the two-spring system, the piston is suspended against gravity between upper and lower springs. In the spring-stop system, the piston is pushed up against a stop by a lower spring. Model and experimental results agree closely for both systems and for different bellows properties.

scholarly journals Reduced Mass-Weighted Proper Decomposition for Modal Analysis

2008 ◽  
Author(s):  
Venkata K. Yadalam ◽  
B. F. Feeny
Keyword(s):  
Modal Analysis ◽  
Mass Distribution ◽  
Mass Matrix ◽  
Linear Interpolation ◽  
Modal Identification ◽  
Lumped Mass ◽  
Arbitrary Mass ◽  
Spring System ◽  
Mass Spring ◽  
Proper Orthogonal

A method of modal analysis by proper orthogonal decomposition for large-order systems of arbitrary mass distribution is outlined. The method involves reduced-order modeling of the system mass distribution so that the discretized mass matrix dimension matches the number of sensed quantities, and hence the dimension of the response ensemble and correlation matrix. In this case, the linear interpolation of unsensed displacements is used to perform an effective lumped mass homogenization. The idea is applied to the modal identification of a mass-spring system and an exponential rod.

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