Three dimensional large scale earthquake simulator with six degrees of freedom

1998 ◽  
Vol 11 (3) ◽  
pp. 387-390 ◽  
Author(s):  
Jun-Wei Han ◽  
Yu-Ting Li ◽  
Bao-Sheng Hu
Keyword(s):  
Degrees Of Freedom ◽  
Large Scale ◽  
Three Dimensional ◽  
Six Degrees Of Freedom ◽  
Earthquake Simulator

On the Radiation and Diffraction of Surface Waves by Submerged Spheroids

1989 ◽  
Vol 33 (02) ◽  
pp. 84-92
Author(s):  
G. X. Wu ◽  
R. Eatock Taylor
Keyword(s):  
Degrees Of Freedom ◽  
Velocity Potential ◽  
Three Dimensional ◽  
Added Mass ◽  
Wave Radiation ◽  
Legendre Functions ◽  
Incoming Wave ◽  
Six Degrees Of Freedom ◽  
Damping Coefficients ◽  
Exciting Forces

The problem of wave radiation and diffraction by submerged spheroids is analyzed using linearized three-dimensional potential-flow theory. The solution is obtained by expanding the velocity potential into a series of Legendre functions in a spheroidal coordinate system. Tabulated and graphical results are provided for added mass and damping coefficients of various spheroids undergoing motions in six degrees of freedom. Graphs are also provided for exciting forces and moments corresponding to a range of incoming wave angles.

Development of a Numerical Method for the Calculation of Power Absorption by Arrays of Similar Arbitrarily Shaped Bodies in a Seaway

1982 ◽  
Vol 26 (01) ◽  
pp. 38-44
Author(s):  
James H. Duncan ◽  
Clinton E. Brown
Keyword(s):  
Wave Energy ◽  
Degrees Of Freedom ◽  
Linear Array ◽  
Three Dimensional ◽  
Computational Procedure ◽  
Hydrodynamic Theory ◽  
Optimal Solutions ◽  
Power Absorption ◽  
Six Degrees Of Freedom ◽  
First Order

A computational procedure is developed using first-order hydrodynamic theory to predict the motions and power absorption from arrays of similar three-dimensional buoys. The buoy shape and the number and placement of the buoys may be arbitrarily selected. The program provides for waves of selected frequency and direction or combinations thereof by simple superposition; thus, the effects on energy absorption of wave energy spectral distributions or short-crestedness can be analyzed. The computer model has been validated by comparison of its results with published analytically derived power optimal solutions for five buoys in a linear array. The program provides the power output of each buoy in the array with the associated motions in six degrees of freedom. The limited number of cases studied has provided the interesting result that identical buoys in an array tend to absorb wave energy at rates close to those of optimized systems for which buoy amplitude and phasing would have to be controlled.

A Three-Dimensional Dynamic Model for Determining the Equilibrium Configurations of Buoyantly Unstable Icebergs

1990 ◽  
Vol 112 (3) ◽  
pp. 253-262
Author(s):  
R. G. Jessup ◽  
S. Venkatesh
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Static Potential ◽  
Initial State ◽  
Model Simulations ◽  
Six Degrees Of Freedom ◽  
Equilibrium Configurations ◽  
Variation Range

This paper describes a dynamic model developed for the purpose of determining the final equilibrium configurations of buoyantly unstable icebergs. The model places no restrictions on the size, shape, or dimensionality of the iceberg, or on the variation range of the configuration coordinates. Furthermore, it includes all six degrees of freedom and is based on a Lagrangian formulation of the dynamic equations of motion. It can be used to advantage in those situations in which the iceberg has a complicated potential function and can acquire enough momentum and kinetic energy in the initial phase of its motion to make its final configuration uncertain on the basis of a static potential analysis. The behavior of the model is examined through several model simulations. The sensitivity of the final equilibrium position to the initial orientation and shape of the iceberg is clearly evident in the model simulations. Model simulations also show that when an iceberg is released from a nonequilibrium initial state, the time taken for it to settle down varies from about 40 s for a growler to nearly 400 s for a large iceberg. While these absolute times may change with better parameterization of the forces, the relative variations with iceberg size are likely to be preserved.

Study on Deformation Law About Six Degrees of Freedom Circular Foundation of Seabed

2012 ◽  
Author(s):  
Qiyi Zhang ◽  
Qinghua Wang ◽  
Ying Zhang ◽  
Qi Wang
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Combined Loading ◽  
Ocean Engineering ◽  
Engineering Structures ◽  
Concentrated Force ◽  
Six Degrees Of Freedom ◽  
Deformation Law ◽  
Vertical Gravity ◽  
Elastic Mechanics

Some foundations of Ocean engineering structures are always in addition to withstand the vertical gravity loads, but also to horizontal loads induced by sea wave and current, which makes the foundation subjected to concentrated force, overturning loads and torque loads, the above loading state including vertical, horizontal and overturning moment loads are termed combined loading. So it is very necessary for the safety of ocean engineering structures to study the deformation law of submarine seabed due to combined loading. On the basis of the three-dimensional elastic mechanics solution of circular foundations, the deformation law of submarine clay under circular foundation with six degrees of freedom is analyzed in detail using numerical calculation methods. Based on the above numerical results, this paper gives the elastic deformation law of clay in three dimensional spaces, gives a modification to the traditional elasticity theoretical solutions, and gives clay coupled deformation mechanism under three-dimensional circular foundation with six degrees of freedom.

The Qualitative Synthesis of Parallel Manipulators

2004 ◽  
Vol 126 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Jorge Angeles
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Parallel Manipulators ◽  
Qualitative Reasoning ◽  
Rigid Bodies ◽  
Three Dimensions ◽  
Qualitative Synthesis ◽  
Motion Representation ◽  
Six Degrees Of Freedom ◽  
Three Degrees Of Freedom

As shown in this paper, when designing parallel manipulators for tasks involving less than six degrees of freedom, the topology can be laid out by resorting to qualitative reasoning. More specifically, the paper focuses on cases whereby the manipulation tasks pertain to displacements with the algebraic structure of a group. Besides the well-known planar and spherical displacements, this is the case of displacements involving: rotation about a given axis and translation in the direction of the same axis (cylindrical subgroup); translation in two and three dimensions (two- and three-dimensional translation subgroups); three independent translations and rotation about an axis of fixed direction, what is known as the Scho¨nflies subgroup; and similar to the Scho¨nflies subgroup, but with the rotation and the translation in the direction of the axis of rotation replaced by a screw displacement. For completeness, the fundamental concepts of motion representation and groups of displacements, as pertaining to rigid bodies, are first recalled. Finally, the concept of Π-joint, introduced elsewhere, is generalized to two and three degrees of freedom, thereby ending up with the Π2-and the Π3-joints, respectively.

Dynamic Modeling and Optimization on the Automatic Balancing of a Washing Machine

2014 ◽  
Vol 620 ◽  
pp. 304-309 ◽  
Author(s):  
Zhong Kun Hong ◽  
Yun Fei Chen
Keyword(s):  
Degrees Of Freedom ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Body System ◽  
Washing Machine ◽  
Machine Model ◽  
Six Degrees Of Freedom ◽  
Design Cycle ◽  
Good Consistency ◽  
Automatic Balancing

In order to study the dynamic performance with respect to a drum type washing machine, a detailed three dimensional dynamic model considering six degrees of freedom is established in the commercial software Adams. The characteristics of model are in good consistency with the simulation results on the movement of measure point in the x-z plane and eigen modes of the rigid body system. An automatic counterbalancing model of balls with different torsion damping coefficient is designed for vibration reduction. The parameters affecting the vibration are investigated by the approach of design of experiments which can reduce design cycle significantly. Its optimization results show a good performance compared to a washing machine model without balance balls attached.

Numerical Simulation of Projectile Accelerating Process in Aftereffect Period

2012 ◽  
Vol 236-237 ◽  
pp. 576-580
Author(s):  
Yang Zhong ◽  
Liang Ming Wang
Keyword(s):  
Numerical Simulation ◽  
Initial Velocity ◽  
Degrees Of Freedom ◽  
Large Scale ◽  
Six Degrees Of Freedom ◽  
After Effect ◽  
Rigid Model ◽  
Peak Value

The initial velocity of a projectile has great effects on the weapon performances and it influences firing accuracy. It is meaningful to know the motion of projectiles in after-effect period. This article studies the motion of the projectile by using a Six Degrees-of-Freedom rigid model and chimera method, which is suitble to simulate large-scale deplacemengt of projectiles. The results of the simulation show that the velocity of the projectile increases rapidly first and decreases slowly after reaching the peak value.

Quaternion-Based Algorithm for Direct Kinematic Model of a Kawasaki FS10E Articulated Arm Robot

2015 ◽  
Vol 762 ◽  
pp. 249-254 ◽  
Author(s):  
Stelian Popa ◽  
Alexandru Dorin ◽  
Florin Adrian Nicolescu ◽  
Andrei Mario Ivan
Keyword(s):  
Degrees Of Freedom ◽  
Dimensional Space ◽  
Kinematic Model ◽  
Three Dimensional ◽  
Number System ◽  
Simulation Software ◽  
Six Degrees Of Freedom ◽  
Mathematical Algorithm ◽  
Development And Validation ◽  
Three Dimensional Space

This article follows a detailed description of development and validation for the direct kinematic model of six degrees of freedom articulated arm robot - Kawasaki FS10E model. The development of the kinematic model is based on widely used Denavit-Hartenberg notation, but, after the initial parameter identification, the mathematical algorithm itself follows an approach that uses the quaternion number system, taking advantage of their efficiency in describing spatial rotation - providing a convenient mathematical notation for expressing rotations and orientations of objects in three-dimensional space. The proposed algorithm concludes with two quaternion-based relations that express both the position of robot tool center point (TCP) position and end-effector orientation with respect to robot base coordinate system using Denavit-Hartenberg parameters and joint values as input data. Furthermore, the developed direct kinematic model was validated using the programming and offline simulation software Kawasaki PC Roset.

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