Toward a New Modeling Paradigm for Constrained Mechanical Systems

1994 ◽  
Vol 116 (1) ◽  
pp. 80-87
Author(s):  
T. M. Hodges ◽  
P. N. Sheth
Keyword(s):  
Nonholonomic Constraints ◽  
Matrix Analysis ◽  
Joint Models ◽  
Modeling Framework ◽  
Constrained Mechanical Systems ◽  
Modeling Paradigm ◽  
The Matrix ◽  
Comprehensive Modeling ◽  
Coordinate Partitioning ◽  
Special Case

The motivational background and a comprehensive modeling framework for incorporating localized design details of joints in the overall multibody models are described in this paper. A direct contact model of two bodies in contact is utilized as a basic building block to develop spatial kinematic analysis procedures based on matrix analysis. A substructure partitioning method for large, detailed models and the concept of local Jacobians for localized joint models is introduced. The nonholonomic constraints are directly incorporated in the matrix method, with the special case of rolling without slipping described in this paper. The coordinate partitioning process is shown to play a fundamental role in the simulation algorithms. The developments reported in this paper represent initial steps toward a comprehensive modeling paradigm for multibody systems with a focus on the localized details of contacts between the bodies.

THE MODELLING OF HOLONOMIC MECHANICAL SYSTEMS USING A NATURAL ORTHOGONAL COMPLEMENT

1989 ◽  
Vol 13 (4) ◽  
pp. 81-89 ◽  
Author(s):  
J. ANGELES ◽  
SANGKOO LEE
Keyword(s):  
Mechanical Systems ◽  
Nonholonomic Constraints ◽  
Kinematic Chain ◽  
Chain Structure ◽  
Rigid Bodies ◽  
Orthogonal Complement ◽  
Constraint Forces ◽  
Constrained Mechanical Systems ◽  
Constraint Equations ◽  
The Matrix

A computationally efficient and systematic algorithm for the modelling of constrained mechanical systems is developed and implemented in this paper. With this algorithm, the governing equations of mechanical systems comprised of rigid bodies coupled by holonomic constraints are derived by means of an orthogonal complement of the matrix of the velocity-constraint equations. The procedure is applicable to all types of holonomic mechanical systems, and it can be extended to cases including simple nonholonomic constraints. Holonomic mechanical systems having a simple Kinematic-chain structure, such as single-loop linkages and serial-type robotic manipulators, are analysed regarding the derivation of the matrix of the constraint equations and its orthogonal complement, and the computation of the constraint forces.

Determination of the phase structure of polymerblends by electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 492-493
Author(s):  
Dr. G. Kaemof
Keyword(s):  
Screw Extruder ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Single Screw Extruder ◽  
Transmission Electron ◽  
The Matrix ◽  
Twin Screw ◽  
Special Case ◽  
Microscopic Investigations

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.

scholarly journals The Categorization and Structural Prediction of Transition Metal Carbonyl Clusters Using 14n Series Numerical Matrix

2016 ◽  
Vol 8 (1) ◽  
pp. 109
Author(s):  
Enos Masheija Rwantale Kiremire
Keyword(s):  
Transition Metal ◽  
Valence Electron ◽  
Metal Carbonyl ◽  
Electron Content ◽  
Constant Number ◽  
Carbonyl Clusters ◽  
Structural Prediction ◽  
Metal Carbonyl Clusters ◽  
The Matrix ◽  
Special Case

<p>A matrix table of valence electron content of carbonyl clusters has been created using the 14n-based series. The numbers so generated form an array of series which conform precisely with valence electron contents of carbonyl clusters. The renowned 18 electron rule is a special case of 14n+4 series. Similarly, the 16 electron rule is another special case of the 14n+2 series. Categorization of the carbonyl clusters using the matrix table of series has been demonstrated. The table is so organized that clusters numerically represented can easily be compared and analyzed. The numbers that are diagonally arranged from right to left represent capping series. The row from right to left represents a decrease in valence electron content with increase in cluster linkages. The variation of cluster shapes of constant number of skeletal elements especially four or more may be monitored or compared with the variation with the valence electron content.</p>

scholarly journals Pengembangan Pasar Tenun Serat PT Retota Sakti Kabupaten Pekalongan, Jawa Tengah

2014 ◽  
Vol 9 (1) ◽  
pp. 54-66
Author(s):  
Hari Subagyo ◽  
Mochamad Hasjim Bintoro ◽  
Parulian Hutagaol
Keyword(s):  
Production Management ◽  
Swot Analysis ◽  
Production Capacity ◽  
Marketing Strategies ◽  
Matrix Analysis ◽  
Key Factors ◽  
Five Factors ◽  
The Matrix ◽  
Market Needs ◽  
Internal And External Factors

Potential weaving industry nationally as one of the SMEs so far have not unearthed the maximum due to the development of production management systems. Therefor,  PT Retota Sakti has prompted company management to enhance the creative abilities tenunnya always accompanied by the application of more precise marketing strategies that correspond with the development of competition situation that occurred in the weaving industry. The purpose of this study was (1) Identify and evaluate the position of Marketing PT Retota Way by internal and external factors, and (2) Develop appropriate marketing strategies in developing future business. Analyzed in a descriptive study to emphasize the aspect of marketing, covering demand products to meet market needs; offer, which gives an overview about the availability of products in the process of cultivation and the balance of factors between demand and supply prices. To examine the marketing strategies carried out by quantitative SWOT analysis. The results of factor identification strategy, there are five key factors of internal strengths and weaknesses of four key factors. While the external environment there are five key factors of opportunities and threats of five factors. IFE values ​​2.842 and 2.530 EFE value, and also the combination of these two values ​​in the matrix IE indicates that the marketing strategy lies in the quadrant of five, namely the growth and stability, where the strategies that can run the market penetration, product development and market. QSP matrix analysis results obtained with the most attractive strategy to be implemented is to increase production capacity.

Comprehensive Modeling Framework to Integrate External Trips in a Travel Demand Model

2019 ◽  
Vol 33 (3) ◽  
pp. 04019011
Author(s):  
Syed Fazal Abbas Baqueri ◽  
Muhammad Adnan ◽  
Tom Bellemans ◽  
Davy Janssens
Keyword(s):  
Travel Demand ◽  
Demand Model ◽  
Modeling Framework ◽  
Comprehensive Modeling ◽  
Travel Demand Model

Study on Kinematics Sensitivities of Folder Mechanism with Clearance

2011 ◽  
Vol 121-126 ◽  
pp. 4764-4769
Author(s):  
Ying Cai Yuan ◽  
Yan Li ◽  
Yi Ming Wang ◽  
Qiang Guo
Keyword(s):  
Sensitivity Analysis ◽  
High Velocity ◽  
High Speed ◽  
Development Trend ◽  
Matrix Analysis ◽  
Analysis Model ◽  
Design Variables ◽  
The Matrix ◽  
The Stability ◽  
Definition Of

High velocity and stability are the development trend and inevitable requirement, but the clearance would make the stability of mechanical system deceased, especially in high speed. To the folder mechanism with clearances in high velocity, combined with the definition of sensitivity and the kinematics analysis, the kinematics sensitivity analysis model is derived by the matrix analysis method. Through the sensitivity analysis model, it can be easy to get the relationship of the design variables and the mechanism’s robustness, which provides the base to design the folder mechanism in high velocity.

Micromechanics Approach for the Overall Elastic Properties of Ceramic Matrix Composites Incorporating Defect Structures

2021 ◽  
Author(s):  
Rajesh Kumar
Keyword(s):  
Elastic Properties ◽  
Volume Fraction ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Matrix Composites ◽  
Defect Structures ◽  
Modeling Framework ◽  
Linear Elastic ◽  
Elastic Tensor ◽  
The Matrix

Abstract Initial mechanical behavior of Ceramic Matrix Composites (CMCs) is linear until the proportional limit. This initial behavior is characterized by linear elastic properties, which are anisotropic due to the orientation and arrangement of fibers in the matrix. The linear elastic properties are needed during analysis and design of CMC components. CMCs are made with ceramic unidirectional or woven fiber preforms embedded in a ceramic matrix formed via various processing routes. The matrix processing of interest in this work is the Polymer Impregnation and Pyrolysis (PIP) process. As this process involves pyrolysis to convert a pre-ceramic polymer into ceramic, considerable volume shrinkage occurs in the material. This leads to significant defects in the form of porosity of various size, shape, and volume fraction. These defect structures can have a significant impact on the elastic and damage response of the material. In this paper, we develop a new micromechanics modeling framework to study the effects of processing-induced defects on linear elastic response of a PIP-derived CMC. A combination of analytical and computational micromechanics approaches is used to derive the overall elastic tensor of the CMC as a function of the underlying constituents and/or defect structures. It is shown that the volume fraction and aspect ratio of porosity at various length-scales plays an important role in accurate prediction of the elastic tensor. Specifically, it is shown that the through-thickness elastic tensor components cannot be predicted accurately using the micromechanics models unless the effects of defects are considered.

Pipe resistance coefficients identification of water networks considering solvable conditions

2020 ◽  
Author(s):  
Yongxin Liu ◽  
Qingting Du ◽  
Peng Luo ◽  
Pinghua Zou ◽  
Zhongyi He
Keyword(s):  
Linearization Method ◽  
Matrix Analysis ◽  
Analysis Process ◽  
Analysis Theory ◽  
Hydraulic Conditions ◽  
The Matrix ◽  
Successive Linearization Method ◽  
Minimum Number ◽  
Coefficients Identification ◽  
Resistance Coefficients

To make hydraulic models more accurate and realistic, this paper proposes a method to identify pipe resistance coefficients (PRCs) by using the measured heads at partial nodes. A successive linearization method is adopted to solve for the pipe flows, node heads, and PRCs. Based on the matrix analysis theory, the relationships among the number and location of measurement sites, number of hydraulic conditions (HCs), and solvable condition of PRC identification are established. The proposed method can identify all the PRCs when a solvable condition can be satisfied. In addition, the analysis process can be used as a tool to evaluate whether a given arrangement of measurement sites can meet the solvable condition of PRC identification, and to determine the minimum number of HCs. The performed case studies verified the feasibility of the proposed method, and the determined accuracy of PRC identification was noted to satisfy the actual engineering requirements.

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