Modeling of Geometric Variations Within a Tolerance-Zone for Circular Runout

2009 ◽  
Author(s):  
Patrick J. Clasen ◽  
Joseph K. Davidson ◽  
Jami J. Shah
Keyword(s):  
Cross Section ◽  
Transverse Cross Section ◽  
Tolerance Zone ◽  
Iso Standards ◽  
Geometric Tolerances ◽  
Short Cylinder ◽  
Tolerance Zones ◽  
First Time

The geometric variations in a tolerance-zone can be modeled with hypothetical point-spaces called Tolerance-Maps (T-Maps) for purposes of automating the assignment of tolerances during design. The objective of this paper is to extend this model to represent tolerances on circular runout which limit geometric manufacturing variations to a specified tolerance-zone. Such a zone is an annular area at one transverse cross-section for spherical, conical, or cylindrical objects (features), but it is a short cylinder when the feature is a round or annular segment of a plane. Depending on the kind of feature and the tolerances that are specified for it, the model may be used to represent variations within tolerance-zones for circular runout, size, position, orientation, and form. In this paper, the Tolerance-Map (T-Map) is a hypothetical volume of points that captures all the circular variations that can arise from these tolerances. The model is compatible with the ASME/ANSI/ISO Standards for geometric tolerances. T-Maps have been generated for other classes of geometric tolerances in which the variation of the feature are represented with a plane or line, and these have been incorporated into testbed software for aiding designers when assigning tolerances for assemblies. In this paper the T-Map for circular runout is created and, for the first time, circles are used to represent the geometric variations of a feature in tolerance-zones.

Formation of Geometric Tolerance Zones for Polyhedral Objects

1997 ◽  
Author(s):  
Utpal Roy ◽  
Bing Li
Keyword(s):  
Variational Model ◽  
Tolerance Zone ◽  
Geometric Tolerance ◽  
Geometric Tolerances ◽  
Polyhedral Objects ◽  
Different Types ◽  
Tolerance Zones ◽  
Algebraic Constraints ◽  
Size Tolerance ◽  
Part Model

Abstract This paper presents a scheme for establishing geometric tolerance zones for polyhedral objects in solid modelers. The proposed scheme is based on a surface-based variational model. Variations are applied to a part model by varying each surface’s model variables. Those model variables are constrained by some algebraic relations derived from the specified geometric tolerances. For size tolerance, two types of tolerance zones are considered in order to reflect two different types of size tolerances. For any other geometric tolerance (form, orientation or positional), the resultant tolerance zone is defined by the combination of size tolerance and that particular geometric tolerance specifications. Appropriate algebraic constraints (on the model variables) are finally used to establish the tolerance zone boundaries in the surface-based variational model.

Modeling of Geometric Variations for Line-Profiles

2011 ◽  
Author(s):  
Joseph K. Davidson ◽  
Jami J. Shah
Keyword(s):  
Two Dimensional ◽  
Line Profiles ◽  
Tolerance Zone ◽  
Geometric Tolerances ◽  
True Profile ◽  
Profile Tolerance ◽  
On Line ◽  
Model Features ◽  
Tolerance Accumulation ◽  
First Time

The geometric variations in a tolerance-zone can be modeled with hypothetical point-spaces called Tolerance-Maps (T-Maps) for purposes of automating the assignment of tolerances during design. The objective of this paper is to extend this model to represent tolerances on line-profiles. Such tolerances limit geometric manufacturing variations to a specified two-dimensional tolerance-zone, i.e. an area, the boundaries to which are curves parallel to the true profile. The single profile tolerance may be used to control position, orientation, and form of the profile. In this paper, the Tolerance-Map (Patent No. 6963824) is a hypothetical volume of points that captures all the positions for the true profile, and those curves parallel to it, which can reside in the tolerance-zone. The model is compatible with the ASME/ANSI/ISO Standards for geometric tolerances. T-Maps have been generated for other classes of geometric tolerances in which the variation of the feature are represented with a plane, line or circle, and these have been incorporated into testbed software for aiding designers when assigning tolerances for assemblies. In this paper the T-Map for line-profiles is created and, for the first time in this model, features may be either symmetrical or non-symmetrical simple planar curves, typically closed. To economize on length of the paper, and yet to introduce a method whereby T-Maps may be used to optimize the allocation of tolerances for line-profiles, the scope of the paper has been limited to square, rectangular, and triangular shapes. An example of tolerance accumulation is presented to illustrate this method.

Modeling of Geometric Variations for Line-Profiles

2012 ◽  
Vol 12 (4) ◽  
Author(s):  
Joseph K. Davidson ◽  
Jami J. Shah
Keyword(s):  
Two Dimensional ◽  
Line Profiles ◽  
Tolerance Zone ◽  
Geometric Tolerances ◽  
True Profile ◽  
Profile Tolerance ◽  
On Line ◽  
Model Features ◽  
Tolerance Accumulation ◽  
First Time

The geometric variations in a tolerance-zone can be modeled with hypothetical point-spaces called Tolerance-Maps (T-Maps) for purposes of automating the assignment of tolerances during design. The objective of this paper is to extend this model to represent tolerances on line-profiles. Such tolerances limit geometric manufacturing variations to a specified two-dimensional tolerance-zone, i.e., an area, the boundaries to which are curves parallel to the true profile. The single profile tolerance may be used to control position, orientation, and form of the profile. In this paper, the Tolerance-Map (Patent No. 6963824) is a hypothetical volume of points that captures all the positions for the true profile, and those curves parallel to it, which can reside in the tolerance-zone. The model is compatible with the ASME/ANSI/ISO Standards for geometric tolerances. T-Maps have been generated for other classes of geometric tolerances in which the variations of the feature are represented with a plane, line or circle, and these have been incorporated into testbed software for aiding designers when assigning tolerances for assemblies. In this paper the T-Map for line-profiles is created and, for the first time in this model, features may be either symmetrical or nonsymmetrical simple planar curves, typically closed. To economize on length of the paper, and yet to introduce a method whereby T-Maps may be used to optimize the allocation of tolerances for line-profiles, the scope of the paper has been limited to square, rectangular, and triangular shapes. An example of tolerance accumulation is presented to illustrate this method.

Study on the Applied Tolerances Using Computer Aided Design

2016 ◽  
Vol 822 ◽  
pp. 50-53
Author(s):  
Nicolae Craciunoiu ◽  
Ana Balanoiu
Keyword(s):  
Computer Aided Design ◽  
3D Model ◽  
Skin Model ◽  
Tolerance Zone ◽  
Iso Standards ◽  
The Real ◽  
Geometric Tolerances ◽  
Computer Aided ◽  
Aided Design ◽  
Geometric Definition

Based on the ISO standards, that give the geometric definition and interpretation of tolerances, this paper propose o representation and interpretation for the geometric tolerances applied to the real pieces. In order to do that, based on the 2D layout of the part, a 3D model of the real piece (skin model) is developed. Then, the datum surface and tolerance zone are applied and explained.

An effectiveness of training program on COVID-19 among healthcare students: A cross section study

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1250-1254
Author(s):  
Kurvatteppa Halemani ◽  
Merlin Cheema ◽  
Shabana Khatun ◽  
Yadidya ◽  
Bhumika Singh ◽  
...  
Keyword(s):  
Nursing Students ◽  
Training Program ◽  
Cross Section ◽  
Sampling Technique ◽  
Teaching Session ◽  
Post Intervention ◽  
Post Test ◽  
College Of Nursing ◽  
Novel Coronavirus ◽  
First Time

The pandemic COVID-19 is a highly infected disease caused by a novel coronavirus or SARS-Cov-2. The virus was reported for the first time  December 2019 in, China's Wuhan province. Later the virus has broken down into the world and claimed millions of lives. In India, the disease was reported for the first time in Kerala on 30th January 2020. a cross-section one group pre-test & post-test research design was used among the 40 final year BSc nursing students, College of Nursing SGPGIMS, Lucknow India. Samples were selected based on purposive sampling technique and sample criteria. An instrument, the first tool included demographic characteristics Similarly, second instrument used for knowledge assessment. After pre-test assessment, a teaching session was held at the seminar room, college of nursing SGPGIMS Lucknow, India. Subsequently post assessment was held after intervention.  A total of 40 participants responded to the study. Demographic variables like 30(75%) participants had less than 22 years of age, 22(55%) were girls, 14(35%) families income found INR 10000-15000, and the majority of participants obtained COVID-19 related knowledge from news paper16(40%). A gender was found significant with pretest knowledge, and other variables weren't found significant (P=0.05). Knowledge mean & standard deviation in pre & post-intervention, 11.90±2.16 vs15.82±1.39. The mean difference was found in a pre-test & post-test-1 &post-test-2, 3.9, 5.02, & 1.1, respectively. The effectiveness of the training program was checked by paired t-test -10.20 & -13.93, P=0.00.  The study revealed that the teaching session was efficient in the COVID-19 program among BSc nursing students.

scholarly journals On the shape of cicada’s wing leading-edge cross section

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachel M. Starkweather ◽  
Svetlana V. Poroseva ◽  
David T. Hanson
Keyword(s):  
Cross Section ◽  
Insect Flight ◽  
Leading Edge ◽  
Flight Performance ◽  
Cross Section Shape ◽  
Section Shape ◽  
First Time

AbstractAn important role that the leading-edge cross-section shape plays in the wing flight performance is well known in aeronautics. However, little is known about the shape of the leading-edge cross section of an insect’s wing and its contribution to remarkable qualities of insect flight. In this paper, we reveal, in the first time, the shape of the leading-edge cross section of a cicada’s wing and analyze its variability along the wing. We also identify and quantify similarities in characteristic dimensions of this shape in the wings of three different cicada species.

Adaptation of Cardinal Points Symmetry Landmarks Distribution Model to in-vivo B-Mode Ultrasound Images of Transverse Cross-section of Carotid Arteries

2021 ◽  
Vol 6 (7) ◽  
pp. 107-113
Author(s):  
Charles Nnamdi Udekwe ◽  
Akinlolu Adediran Ponnle
Keyword(s):  
Carotid Artery ◽  
Cross Section ◽  
Carotid Arteries ◽  
Region Of Interest ◽  
Transverse Cross Section ◽  
Transverse Plane ◽  
Distribution Model ◽  
Ultrasound Images ◽  
Symmetry Line

The geometry of the imaged transverse cross-section of carotid arteries in in-vivo B-mode ultrasound images are most times irregular, unsymmetrical, full of speckles and usually non-uniform. We had earlier developed a technique of cardinal point symmetry landmark distribution model (CPS-LDM) to completely characterize the Region of Interest (ROI) of the geometric shape of thick-walled simulated B-mode ultrasound images of carotid artery imaged in the transverse plane, but this was based on the symmetric property of the image. In this paper, this developed technique was applied to completely characterize the region of interest of the geometric shape of in-vivo B-mode ultrasound images of non-uniform carotid artery imaged in the transverse plane. In order to adapt the CPS-LD Model to the in-vivo carotid artery images, the single VS-VS vertical symmetry line common to the four ROIs of the symmetric image is replaced with each ROI having its own VS-VS vertical symmetry line. This adjustment enables the in-vivo carotid artery images possess symmetric properties, hence, ensuring that all mathematical operations of the CPS-LD Model are conveniently applied to them. This adaptability was observed to work well in segmenting the in-vivo carotid artery images. This paper shows the adaptive ability of the developed CPS-LD Model to successfully annotate and segment in-vivo B-mode ultrasound images of carotid arteries in the transverse cross-sectional plane either they are symmetrical or unsymmetrical.

Evaluation of Actual Geometric Tolerances Using Coordinate Measuring Machine Data

1989 ◽  
Author(s):  
W. H. ElMaraghy ◽  
Z. Wu ◽  
H. A. ElMaraghy
Keyword(s):  
Three Dimensional ◽  
Measurement Data ◽  
Simulated Data ◽  
Coordinate Measuring Machine ◽  
Optimization Techniques ◽  
Test Cases ◽  
Tolerance Zone ◽  
Geometric Tolerances ◽  
Measuring Machine

Abstract This paper focuses on the development of a procedure and algorithms for the systematic comparison of geometric variations of measured features with their specified geometric tolerances. To automate the inspection of mechanical parts, it is necessary to analyze the measurement data captured by coordinate measuring machines (CMM) in order to detect out-of-tolerance conditions. A procedure for determining the geometric tolerances from the measured three dimensional coordinates on the surface of a cylindrical feature is presented. This procedure follows the definitions of the geometric tolerances used in the current Standards, and is capable of determining the value of each geometric tolerance from the composite 3-D data. The developed algorithms adopt the minimum tolerance zone criterion. Nonlinear numerical optimization techniques are used to fit the data to the minimum tolerance zone. Two test cases are given in the paper which demonstrate the successful determination of geometric tolerances from given simulated data.

scholarly journals From Symmetry to Asymmetry: The Use of Additional Pulses to Improve Protection against Ultrashort Pulses Based on Modal Filtration

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1117 ◽  
Author(s):  
Anton O. Belousov ◽  
Evgeniya B. Chernikova ◽  
Mariya A. Samoylichenko ◽  
Artem V. Medvedev ◽  
Alexander V. Nosov ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Cross Section ◽  
Ultrashort Pulses ◽  
Reference Plane ◽  
Modal Decomposition ◽  
Protective Devices ◽  
Modal Filters ◽  
First Time ◽  
Filtration Technology ◽  
Side Coupling

For the first time, the paper considers in a unified work the possibility of the appearance of additional pulses in various structures based on modal filtration technology, which is used to improve protection against ultrashort pulses (USP). We analyzed meander lines (ML) with broad-side coupling, structures with modal reservation (MR), reflection symmetric MLs, and modal filters (MF) with a passive conductor in the reference plane cutout and obtained the following results. It was found that the main reason for the additional pulses to appear in these structures is the introduction of asymmetry (of the cross-section, boundary conditions, and excitation). It is theoretically and experimentally established that additional pulses are a new resource for increasing the efficiency of protective devices with modal decomposition, but the highest effectiveness could be achieved through careful optimization.

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