A Mathematical Model for Geometric Tolerances

1993 ◽  
Vol 115 (1) ◽  
pp. 81-86 ◽  
Author(s):  
F. Etesami
Keyword(s):  
Mathematical Model ◽  
Specification Language ◽  
Theoretic Approach ◽  
One Dimensional ◽  
Dimensional Tolerance ◽  
Geometric Tolerancing ◽  
Geometric Tolerances ◽  
Tolerance Specification ◽  
Tolerance Zones

This paper presents a mathematical model for specifying geometric tolerances. This model along with a syntax of tolerance specification will be referred to as the Tolerance Specification Language (TSL). TSL can be used to interpret ANSI Y14.5 geometric tolerancing specifications. The formalization of TSL is based on a set theoretic approach, especially on the concept of offset solids. In this model there is no classification of tolerance types, and there are no restrictions on the use of feature types. Instead, TSL allows the designer to control a feature from expanding, shrinking, or deforming beyond a specified tolerance value. All the tolerancing assertions in TSL apply to surface features and generate uniform tolerance zones. Using two and one dimensional tolerance specification facilities, TSL can approximate ANSI statements that apply to derived features, or generate non-uniform tolerance zones. The appendix of this paper discusses many examples from ANSI and their equivalent TSL form.

Using Tolerance-Maps to Generate Frequency Distributions of Clearance and Allocate Tolerances for Pin-Hole Assemblies

2007 ◽  
Vol 7 (4) ◽  
pp. 347-359 ◽  
Author(s):  
Gaurav Ameta ◽  
Joseph K. Davidson ◽  
Jami J. Shah
Keyword(s):  
Mathematical Model ◽  
Statistical Method ◽  
Frequency Distribution ◽  
Probabilistic Representation ◽  
Worst Case ◽  
Frequency Distributions ◽  
One Dimensional ◽  
Material Condition ◽  
Geometric Tolerances ◽  
Case Basis

A new mathematical model for representing the geometric variations of lines is extended to include probabilistic representations of one-dimensional (1D) clearance, which arise from positional variations of the axis of a hole, the size of the hole, and a pin-hole assembly. The model is compatible with the ASME/ ANSI/ISO Standards for geometric tolerances. Central to the new model is a Tolerance-Map (T-Map) (Patent No. 69638242), a hypothetical volume of points that models the 3D variations in location and orientation for a segment of a line (the axis), which can arise from tolerances on size, position, orientation, and form. Here, it is extended to model the increases in yield that occur when maximum material condition (MMC) is specified and when tolerances are assigned statistically rather than on a worst-case basis; the statistical method includes the specification of both size and position tolerances on a feature. The frequency distribution of 1D clearance is decomposed into manufacturing bias, i.e., toward certain regions of a Tolerance-Map, and into a geometric bias that can be computed from the geometry of multidimensional T-Maps. Although the probabilistic representation in this paper is built from geometric bias, and it is presumed that manufacturing bias is uniform, the method is robust enough to include manufacturing bias in the future. Geometric bias alone shows a greater likelihood of small clearances than large clearances between an assembled pin and hole. A comparison is made between the effects of choosing the optional material condition MMC and not choosing it with the tolerances that determine the allowable variations in position.

A Survey of Mathematical Methods for the Construction of Geometric Tolerance Zones

2003 ◽  
Vol 3 (1) ◽  
pp. 64-75 ◽  
Author(s):  
T. M. Kethara Pasupathy ◽  
Edward P. Morse ◽  
Robert G. Wilhelm
Keyword(s):  
Functional Requirements ◽  
Mathematical Methods ◽  
Geometric Tolerance ◽  
Manufacturing Enterprises ◽  
Computing Machinery ◽  
Geometric Tolerances ◽  
Tolerance Specification ◽  
Computer Based ◽  
Tolerance Zones ◽  
Application Specific

The physical realization of any part always yields imperfect forms with respect to the ideal geometry specified in the engineering design. To describe and preserve functional requirements of design, the allowable variation is specified using modern geometric tolerances via tolerance zones. Specification using geometric tolerances is intended for unambiguous communication. Mathematically unambiguous specification is required for the application of computing machinery across manufacturing enterprises to lower costs and improve efficiency. Several computer-based tools have been developed to aid in tolerance specification and also in subsequent processing, or applications that utilize tolerance specification information, such as analysis, synthesis, manufacture and measurement. In order to execute these activities, the tolerance zones have to be unambiguously captured by computer programs. The geometric tolerance specification is complex and not completely free of ambiguities. These difficulties pose as challenges in realizing the tolerance zones and limit the applicability of any particular method developed so far. This paper presents a survey of the current computer based methods available to capture tolerance zones of parts. The limitations of the methods are analyzed based on the following criteria: the range of applicability, compatibility with standards, ease in realization and the effects of singularities in shapes that are application specific. Various assembly analysis techniques that utilize the tolerance zone construction and other recent approaches for tolerance design are also reported.

Research on cargo-loading optimization based on genetic and fuzzy integration

2021 ◽  
Vol 40 (4) ◽  
pp. 8493-8500
Author(s):  
Yanwei Du ◽  
Feng Chen ◽  
Xiaoyi Fan ◽  
Lei Zhang ◽  
Henggang Liang
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Three Dimensional ◽  
Distribution Center ◽  
Long Time ◽  
Low Efficiency ◽  
Decision Making Model ◽  
The Mathematical Model ◽  
Loading Scheme

With the increase of the number of loaded goods, the number of optional loading schemes will increase exponentially. It is a long time and low efficiency to determine the loading scheme with experience. Genetic algorithm is a search heuristic algorithm used to solve optimization in the field of computer science artificial intelligence. Genetic algorithm can effectively select the optimal loading scheme but unable to utilize weight and volume capacity of cargo and truck. In this paper, we propose hybrid Genetic and fuzzy logic based cargo-loading decision making model that focus on achieving maximum profit with maximum utilization of weight and volume capacity of cargo and truck. In this paper, first of all, the components of the problem of goods stowage in the distribution center are analyzed systematically, which lays the foundation for the reasonable classification of the problem of goods stowage and the establishment of the mathematical model of the problem of goods stowage. Secondly, the paper abstracts and defines the problem of goods loading in distribution center, establishes the mathematical model for the optimization of single car three-dimensional goods loading, and designs the genetic algorithm for solving the model. Finally, Matlab is used to solve the optimization model of cargo loading, and the good performance of the algorithm is verified by an example. From the performance evaluation analysis, proposed the hybrid system achieve better outcomes than the standard SA model, GA method, and TS strategy.

scholarly journals Classification of one-dimensional superattracting germs in positive characteristic

2014 ◽  
Vol 35 (7) ◽  
pp. 2242-2268 ◽  
Author(s):  
MATTEO RUGGIERO
Keyword(s):  
Positive Characteristic ◽  
Closed Field ◽  
Algebraically Closed Field ◽  
One Dimensional ◽  
Higher Dimensional ◽  
Dimensional Version

We give a classification of superattracting germs in dimension $1$ over a complete normed algebraically closed field $\mathbb{K}$ of positive characteristic up to conjugacy. In particular, we show that formal and analytic classifications coincide for these germs. We also give a higher-dimensional version of some of these results.

Infiltration in Unsaturated Frozen Soil

1984 ◽  
Vol 15 (4-5) ◽  
pp. 243-252 ◽  
Author(s):  
Helén Engelmark
Keyword(s):  
Mathematical Model ◽  
Simulated Data ◽  
Frozen Soil ◽  
Thermal Parameters ◽  
Field Observations ◽  
Snow Melt ◽  
One Dimensional ◽  
Run Off ◽  
Melt Infiltration

A one-dimensional mathematical model is used to simulate the process of snow-melt infiltration in unsaturated frozen silt. Hydraulic and thermal parameters are mainly based on data given in the literature. Field observations in a watershed (of area 1.8 km2) are compared with simulated data and consequences on snow melt run-off are discussed.

Invariants of weak equivalence in primitive matrices

2000 ◽  
Vol 20 (2) ◽  
pp. 611-626 ◽  
Author(s):  
RICHARD SWANSON ◽  
HANS VOLKMER
Keyword(s):  
Inverse Limit ◽  
Direct Application ◽  
Topological Classification ◽  
Weak Equivalence ◽  
Transition Matrices ◽  
Inverse Limit Spaces ◽  
Positive Dimension ◽  
One Dimensional ◽  
Dimension Group

Weak equivalence of primitive matrices is a known invariant arising naturally from the study of inverse limit spaces. Several new invariants for weak equivalence are described. It is proved that a positive dimension group isomorphism is a complete invariant for weak equivalence. For the transition matrices corresponding to periodic kneading sequences, the discriminant is proved to be an invariant when the characteristic polynomial is irreducible. The results have direct application to the topological classification of one-dimensional inverse limit spaces.

scholarly journals Development of One-Dimensional Mathematical Model for Validation of Pulse Diagnosis

2008 ◽  
Vol 74 (737) ◽  
pp. 142-148 ◽  
Author(s):  
Kentaro NARUMI ◽  
Tsutomu NAKANISHI ◽  
Atsushi SHIRAI ◽  
Toshiyuki HAYASE
Keyword(s):  
Mathematical Model ◽  
Pulse Diagnosis ◽  
One Dimensional
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