Towards Dynamic Tolerance Analysis Using Bond Graphs

1998 ◽  
Author(s):  
Otto W. Salomons ◽  
Johan Zijlstra ◽  
Johnny A. van der Zwaag ◽  
Fred J. A. M. van Houten
Keyword(s):  
Dynamic Behavior ◽  
Robust Design ◽  
Physical Modeling ◽  
Geometric Modeling ◽  
Tolerance Analysis ◽  
Simulation System ◽  
Computer Support ◽  
Bond Graphs ◽  
Physical Effects ◽  
Geometric Modeling System

Abstract A generic method is proposed by which the effect of tolerances in combination with physical effects such as wear can be analysed on the dynamic behavior of mechanisms. The method uses bond graphs in order to simulate the dynamic behavior under the influence of tolerances and other physical effects. The method has the potential to offer enhanced computer support in tolerance value specification as well as in robust design and model based maintenance. The method has partly been implemented using a combination of a geometric modeling system (FROOM) and a bond graph based physical modeling and simulation system (20-Sim).

Towards Dynamic Tolerance Analysis Using a Finite Element Formulation

2000 ◽  
Author(s):  
Otto Salomons ◽  
Elmer Arentsen ◽  
Ronald Aarts ◽  
Fred van Houten
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Geometric Model ◽  
Tolerance Analysis ◽  
Element Model ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Large Numbers ◽  
Physical Effects

Abstract A theoretical framework is proposed by which the effect of tolerances can be analyzed. Especially it focuses on the influence of clearances on the dynamic behavior of mechanisms. As opposed to previous publications, where a bondgraph formulation was used, this paper uses a finite element formulation in order to simulate the dynamic behavior under the influence of tolerances and other physical effects. The finite element formulation that has been selected for this work has two major advantages when compared to a bondgraph formulation. The first important advantage is that the method is analytical to a great extent. As a result, no numerically derived derivatives will exist, hence not leading to numeric inaccuracies. The second advantage is that small numbers can be separated from large numbers allowing to separate tolerances from the nominal path, resulting in faster simulations. The paper describes how a geometric model, including its tolerances, can be transformed into a corresponding finite element model that on its part consists of submodels. Based on this model, simulations can be performed which can provide insight in the dynamic behavior of the mechanism. The paper details on how geometric tolerances (such as form, orientation, position as well as size and clearances), with the focus on clearances, can be accounted for in a finite element model.

Design for Assembly Evaluation of Orientation Difficulty Features

1992 ◽  
Author(s):  
Robert H. Sturges ◽  
Jui-Te Yang
Keyword(s):  
Geometric Modeling ◽  
Boundary Representation ◽  
Design For Assembly ◽  
Assembly Process ◽  
Assembly Evaluation ◽  
Index Of Difficulty ◽  
Analysis System ◽  
Time Required ◽  
High Level ◽  
Geometric Modeling System

Abstract In support of the effort to bring downstream issues to the attention of the designer as parts take shape, an analysis system is being built to extract certain features relevant to the assembly process, such as the dimension, shape, and symmetry of an object. These features can be applied to a model during the downstream process to evaluate handling and assemblability. In this paper, we will focus on the acquisition phase of the assembly process and employ a Design for Assembly (DFA) evaluation to quantify factors in this process. The capabilities of a non-homogeneous, non-manifold boundary representation geometric modeling system are used with an Index of Difficulty (ID) that represents the dexterity and time required to assemble a product. A series of algorithms based on the high-level abstractions of loop and link are developed to extract features that are difficult to orient, which is one of the DFA criteria. Examples for testing the robustness of the algorithms are given. Problems related to nearly symmetric outlines are also discussed.

scholarly journals Hardware and Software Implementation of Constructive Geometric Models

2020 ◽  
pp. 83-98
Author(s):  
Denis Voloshinov ◽  
Konstantin Solomonov
Keyword(s):  
Computer Technology ◽  
Geometric Modeling ◽  
Software Implementation ◽  
Theoretical Research ◽  
Graphical Interface ◽  
Calculation Methods ◽  
Geometric Transformations ◽  
Geometric Models ◽  
Long Time ◽  
Geometric Modeling System

The article is devoted to the consideration of a number of issues of hardware and software implementation of constructive geometric models. A rich arsenal of theoretical research in the field of constructive geometry has not been properly used for a long time due to the lack of tools for translating such models using computer technology. The development and improvement of the Simplex geometric modeling system, in which any geometric design is considered as a converter of information represented by signals of a geometric nature, has opened the possibility of applying the achievements of geometric science in computing applications, as well as the development of hardware that implements geometric calculation methods and provides a new graphical interface. The concept developed by the authors is aimed at creating specialized accelerators of geometric transformations.

Curve and Surface Modeling with Uncertainties Using Dual Kriging

1999 ◽  
Vol 121 (2) ◽  
pp. 249-255 ◽  
Author(s):  
A. Limaiem ◽  
H. A. ElMaraghy
Keyword(s):  
Measurement Errors ◽  
Geometric Modeling ◽  
Curve Surface ◽  
Tolerance Analysis ◽  
Kriging Model ◽  
Surface Modeling ◽  
Kriging Interpolation ◽  
Average Deviation ◽  
Dual Kriging ◽  
Potential Applications

This paper presents a new technique based on dual Kriging interpolation for modeling curves and surfaces in the presence of uncertainties in data points. Uncertainties result from measurement errors; therefore, a direct application of this method is found in curve/surface modeling using discrete sets of digitized points. It focuses on a common problem in geometric modeling, the trade-off between curve/surface smoothness and the approximation errors. The Kriging model filters the noise in the data while controlling the deviation locally at each point. However, the classical least-squares technique minimizes the average deviation, hence allowing only a global control of the model. The presented method generates smoother and more accurate representation of the actual curve or surface. It has potential applications in reverse engineering, NC machining, computer-aided inspection and tolerance analysis and verification. Examples of a computer mouse and a portion of the hood of a scaled-down car are presented for illustration.

scholarly journals Interactive Geometric Modeling System based on Practical Engineering Drawings

1984 ◽  
Vol 27 (230) ◽  
pp. 1788-1795
Author(s):  
Tamio AIZAWA ◽  
Kohichi YAMATO ◽  
Masaru NAKAZAWA
Keyword(s):  
Geometric Modeling ◽  
Practical Engineering ◽  
Engineering Drawings ◽  
Geometric Modeling System

Automated Assignment of Physical Effects to Functions Using Ports Based on Bond Graphs

2011 ◽  
Author(s):  
Bergen Helms ◽  
Hansjo¨rg Schultheiß ◽  
Kristina Shea
Keyword(s):  
New Technologies ◽  
Selection Process ◽  
Innovation Process ◽  
Oriented Graph ◽  
Computational Design ◽  
Graph Grammar ◽  
Automated Assignment ◽  
Bond Graphs ◽  
Design Synthesis ◽  
Physical Effects

Innovation processes are highly susceptible to cyclic influences, such as evolving knowledge due to new technologies. In order to cope with these challenge, computational support is required. Paper-based design methods have vast amounts of knowledge at their disposal in the form of design catalogues. However, lacking a computational implementation, these knowledge sources provide no support for considering dynamic influences in the innovation process. The presented method is targeted at making the physical effects contained in design catalogues available for computational design synthesis approaches. For this purpose, this paper introduces the notion of abstraction ports that is used to represent the valid mapping between functional operators and physical effects. For the automated assignment of abstraction ports, a method has been developed that analyzes the equation structure of physical effects. This approach is derived from the modeling technique of bond graphs and is independent of any selection process proposed by design catalogues. Moreover, it allows for the formalization of evolving knowledge in new physical effects that are not yet contained in design catalogues. The assignment of abstraction ports has been successfully validated through the formalization of the physical effects of two design catalogues. Future work comprises the integration of quantitative characteristics of physical effects and the realization within the object-oriented graph grammar system booggie.

scholarly journals Limitations of a dynamic shear-frame model based in a small-scale experimental steel structure

2018 ◽  
Vol 211 ◽  
pp. 14005
Author(s):  
Augusto de S. Pippi ◽  
Pedro L. Bernardes Júnior ◽  
Suzana M. Avila ◽  
Marcus V. G. de Morais ◽  
Graciela Doz
Keyword(s):  
Dynamic Behavior ◽  
Geometric Modeling ◽  
Structural Model ◽  
Natural Frequencies ◽  
Numerical Models ◽  
Steel Structure ◽  
Small Scale ◽  
The Real ◽  
Frame Model ◽  
Shear Frame

Many engineering problems require geometric modeling and mechanical simulation of structures. Through the structural models, engineers try to simulate the real behavior of these structures. It is important that a model contain all the necessary parameters that describe the structure and its behavior during its useful life. In the field of dynamics, one of the most used models is the shear-frame, in which the stiffness of the structure is given by the stiffness of the columns and the whole mass is concentrated in the floor levels, which are considered with infinite stiffness. In some cases, this simplification offers more conservative results, which can lead to considerable errors, especially in the case of natural frequencies. Knowing that the quality of a structural model depends on the simplifications considered, an experimental 3D steel frame, constructed to typify the dynamic behavior of a tall building, was tested with a data acquisition system and accelerometers, in order to obtain its natural frequencies. In addition, a numerical model was developed in order to ascertain the results. These values of natural frequencies are compared with an idealized shear-frame model obtained from the experimental model. This comparison allows a critical analysis of the numerical models that can be employed to represent the real dynamic behavior of structures. The aim of the investigation is to show the results of the modal analysis for each model, comparing them with the experimental results and commenting their advantages and the limitations.

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