Variation Analysis of Compliant Parts in Composite Material Joined by Adhesive: A Numerical Tool

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Andrea Corrado ◽  
Wilma Polini
Keyword(s):  
Composite Material ◽  
Functional Relationship ◽  
Tolerance Analysis ◽  
Variation Analysis ◽  
Geometric Deviations ◽  
Numerical Tool ◽  
Compliant Parts ◽  
The Individual ◽  
Good Agreement

Tolerance analysis defines a procedure to estimate the resultant variation of the assembly geometry, given the tolerances associated with individual components and the functional relationship between the individual components and the assembly requirements. This aspect is particularly relevant when parts made of composite material are considered, since the research emphasis to date was on the design and fabrication of composite parts, with considerably less attention to quality issues in their subsequent assembly. This work presents a numerical tool to solve the tolerance analysis of assemblies made of compliant parts in composite material; it estimates the geometric deviations of an assembly due to the compliance of the material, the geometrical deviations of the components and the fastening of the parts by adhesive. The comparison between numerical and experimental results obtained for a case study shows a good agreement.

Efficient Consideration of Contact in Compliant Assembly Variation Analysis

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Georg Ungemach ◽  
Frank Mantwill
Keyword(s):  
Dimensional Accuracy ◽  
Tolerance Analysis ◽  
Nonlinear Effects ◽  
Variation Analysis ◽  
Compliant Assembly ◽  
Wide Range ◽  
Geometric Deviations ◽  
Statistical Tolerance ◽  
The Individual

The geometric deviations of real parts pose a major challenge, particularly in the extensively automated mass production of complex assemblies. To meet this challenge, an attempt is made, with the aid of statistical tolerance analysis, to predict dimensional accuracy for various assembly concepts as precisely as possible depending on the individual part tolerances. Most recent developments enable consideration to be given to the deformability of the parts during joining in order to improve the prognostic quality of simulation. The methods that are employed reveal deficits if nonlinear effects such as contact, extensive deformations, or material inelasticities occur. In this work, contact between or with adjacent parts during joining will be investigated, and an efficient and reliable method, which can be unproblematically integrated into existing compliant assembly variation analysis programs, will be developed. To achieve this, the methods of springback calculation according to Liu et al. (1995, “Variation Simulation for Deformable Sheet Metal Assemblies Using Mechanistic Models,” Trans. NAMRI/SME, 23, pp. 235–241) have been extended and coupled with numerical contact mechanics methods in order to realistically portray the problem, which usually involves intensive computing, with a minimum of additional effort. The method that has been developed will be validated on the basis of two examples with the aid of nonlinear finite element analyses, the results of which can be regarded as state-of-the-art in mechanical problems involving contact. The quality of the results reveals that this method improves the quality of prognosis for a wide range of applications and, consequently, that production problems can be combated during an early development phase.

scholarly journals Assembly Variation Analysis of Aircraft Panels under Part-to-part Locating Scheme

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xia Liu ◽  
Luling An ◽  
Zhiguo Wang ◽  
Changbai Tan ◽  
Xiaoping Wang ◽  
...  
Keyword(s):  
Elastic Deformation ◽  
Assembly Process ◽  
Variation Analysis ◽  
Kinematic Theory ◽  
Statistical Variation ◽  
Variation Propagation ◽  
Fixed Part ◽  
Compliant Parts ◽  
Aircraft Panels

A typical aircraft panel is the assembly consisting of a multitude of thin and lightweight compliant parts. In panel assembly process, part-to-part locating scheme has been widely adopted in order to reduce fixtures. By this locating scheme, a part is located onto the pre-fixed part/subassembly by determinant assembly (DA) holes, and temporary fasteners (e.g., spring pin) are used for joining these DA hole-hole pairs. The temporary fasteners can fasten DA hole-hole pairs in the axial and radial directions of DA holes. The fastening in the radial directions is realized by the expansion of temporary fasteners. Although the usage of temporary fasteners helps reduce the positional differences between hole-hole pairs, their clamping forces thereby may lead to elastic deformation of compliant parts/subassemblies. Limited research has been conducted on such elastic deformation produced by temporary fastener and its influence on assembly dimensional quality. This paper proposes a novel rigid-compliant variation analysis method for aircraft panel assembly, incorporating the deformation in part-to-part locating process. Based on the kinematic theory and linear elasticity deformation assumption, the variation propagation through the locating process, as well as the entire assembly process of an aircraft panel, is formulated. Then, the statistical variation analysis is performed with Monte Carlo (MC) simulation. Finally, the proposed method is validated by a case study. The result shows the deformation in the part-to-part locating process significantly impacts the assembly variations, and our method can provide a more accurate and reliable prediction.

scholarly journals Scenarios Approach to the Electromagnetic Exposure: The Case Study of a Train Compartment

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
A. Paffi ◽  
F. Apollonio ◽  
R. Pinto ◽  
M. Liberti
Keyword(s):  
Electric Field ◽  
Electromagnetic Fields ◽  
Cell Phones ◽  
International Guideline ◽  
Cell Orientation ◽  
Field Distributions ◽  
Exposure Levels ◽  
The Individual ◽  
Good Agreement

Previous studies identified the train compartment as the place where people can experience the highest exposure levels (still below the international guideline limits) to electromagnetic fields in the radiofrequency range. Here a possible scenario of a train compartment has been reproduced and characterized, both numerically and experimentally. A good agreement between the simulated electric field distributions and measurements has been found. Results indicate that the higher values of exposure in specific positions inside the train compartment depend on the number of active cell phones, the bad coverage condition, the cell orientation, and the presence of metallic walls. This study shows that the proposed approach, based on the scenarios characterization, may efficiently support the assessment of the individual electromagnetic exposure.

Geometric tolerance analysis through Jacobian model for rigid assemblies with translational deviations

2016 ◽  
Vol 36 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Wilma Polini ◽  
Andrea Corrado
Keyword(s):  
Tolerance Analysis ◽  
Geometric Error ◽  
Functional Requirements ◽  
Content Type ◽  
Geometric Tolerances ◽  
Mechanical Assemblies ◽  
Geometric Deviations ◽  
2D And 3D ◽  
Practical Implications

Purpose – The purpose of this paper is to carry out a tolerance analysis with geometric tolerances by means of the Jacobian model. Tolerance analysis is an important task to design and to manufacture high-precision mechanical assemblies; it has received considerable attention by the literature. The Jacobian model is one of the methods proposed by the literature for tolerance analysis. The Jacobian model cannot deal with geometric tolerances for mechanical assemblies. The geometric tolerances may not be neglected for assemblies, as they significantly influence their functional requirements. Design/methodology/approach – This paper presents how it is possible to deal with geometric tolerances when a tolerance analysis is carried out by means of a Jacobian model for a 2D and 3D assemblies for which the geometric tolerances applied to the components involve only translational deviations. The three proposed approaches modify the expression of the stack-up function to overcome the shortage of Jacobian model that the geometric error cannot be processed. Findings – The proposed approach has been applied to a case study. The results of the case study show how, when a statistical approach is implemented, the Jacobian model with the three developed methods gives results very similar to those due to other models of the literature, such as vector loop and variational. Research limitations/implications – In particular, the proposed approach may be applied only when the applied geometrical tolerances involve translational variations in 3D assemblies. Practical implications – Tolerance analysis is a valid tool to foresee geometric interferences among the components of an assembly before getting the physical assembly. It involves a decrease of the manufacturing costs. Originality/value – The original contribution of the paper is due to three methods to make a Jacobian model able to consider form and geometric deviations.

A Parameterized Method for Assembly Tolerance Analysis Based on Deviation Propagation Theory

2013 ◽  
Vol 475-476 ◽  
pp. 1449-1453
Author(s):  
Hai Li ◽  
Yun Feng Leng ◽  
Hai Ping Zhu ◽  
Pei Gen Li
Keyword(s):  
Functional Relationship ◽  
Tolerance Analysis ◽  
Propagation Model ◽  
Analysis Method ◽  
Propagation Theory ◽  
Quality Requirements ◽  
Assembly Tolerance ◽  
Deviation Propagation

The paper proposed a new tolerance analysis method: a unified tolerance and deviation model is adopted to synthesize different kinds of tolerances; an integrated tolerance propagation model is designed to construct the functional relationship between the tolerances and quality requirements. The method is simpler and more widely applicable than the traditional linearization analysis method. A case study is provided to illustrate the proposed method.

The Development of Language-Training Programs for Postrubella Hearing-Impaired Children

1973 ◽  
Vol 38 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Linda Lynch ◽  
Annette Tobin
Keyword(s):  
Hearing Impaired ◽  
Treatment Programs ◽  
Individual Treatment ◽  
Target Behaviors ◽  
Systematic Fashion ◽  
Development Of Language ◽  
The Individual ◽  
Impaired Children ◽  
Hearing Impaired Children

This paper presents the procedures developed and used in the individual treatment programs for a group of preschool, postrubella, hearing-impaired children. A case study illustrates the systematic fashion in which the clinician plans programs for each child on the basis of the child’s progress at any given time during the program. The clinician’s decisions are discussed relevant to (1) the choice of a mode(s) for the child and the teacher, (2) the basis for selecting specific target behaviors, (3) the progress of each program, and (4) the implications for future programming.

‘A Routh O’ Auld Nick-Nackets’ – the antiquarian collection of John Rae

2015 ◽  
Vol 36-37 (1) ◽  
pp. 163-183
Author(s):  
Paul Taylor
Keyword(s):  
United States ◽  
Nineteenth Century ◽  
Social Context ◽  
Moral Education ◽  
The United States ◽  
Representative Case ◽  
National Museums ◽  
The Individual ◽  
The University

John Rae, a Scottish antiquarian collector and spirit merchant, played a highly prominent role in the local natural history societies and exhibitions of nineteenth-century Aberdeen. While he modestly described his collection of archaeological lithics and other artefacts, principally drawn from Aberdeenshire but including some items from as far afield as the United States, as a mere ‘routh o’ auld nick-nackets' (abundance of old knick-knacks), a contemporary singled it out as ‘the best known in private hands' (Daily Free Press 4/5/91). After Rae's death, Glasgow Museums, National Museums Scotland, the University of Aberdeen Museum and the Pitt Rivers Museum in Oxford, as well as numerous individual private collectors, purchased items from the collection. Making use of historical and archive materials to explore the individual biography of Rae and his collection, this article examines how Rae's collecting and other antiquarian activities represent and mirror wider developments in both the ‘amateur’ antiquarianism carried out by Rae and his fellow collectors for reasons of self-improvement and moral education, and the ‘professional’ antiquarianism of the museums which purchased his artefacts. Considered in its wider nineteenth-century context, this is a representative case study of the early development of archaeology in the wider intellectual, scientific and social context of the era.

Drowning in negativism, self-hate, doubt, madness: Linguistic insights into Sylvia Plath’s experience of depression

2015 ◽  
Vol 11 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Zsófia Demjén
Keyword(s):  
Lived Experience ◽  
Medical Humanities ◽  
Sylvia Plath ◽  
Individual Experience ◽  
Qualitative And Quantitative ◽  
The World ◽  
The Individual ◽  
Linguistic Methods ◽  
Linguistic Approach

This paper demonstrates how a range of linguistic methods can be harnessed in pursuit of a deeper understanding of the ‘lived experience’ of psychological disorders. It argues that such methods should be applied more in medical contexts, especially in medical humanities. Key extracts from The Unabridged Journals of Sylvia Plath are examined, as a case study of the experience of depression. Combinations of qualitative and quantitative linguistic methods, and inter- and intra-textual comparisons are used to consider distinctive patterns in the use of metaphor, personal pronouns and (the semantics of) verbs, as well as other relevant aspects of language. Qualitative techniques provide in-depth insights, while quantitative corpus methods make the analyses more robust and ensure the breadth necessary to gain insights into the individual experience. Depression emerges as a highly complex and sometimes potentially contradictory experience for Plath, involving both a sense of apathy and inner turmoil. It involves a sense of a split self, trapped in a state that one cannot overcome, and intense self-focus, a turning in on oneself and a view of the world that is both more negative and more polarized than the norm. It is argued that a linguistic approach is useful beyond this specific case.

THE ROLE OF EDUCATION ON DISASTER PREPAREDNESS CASE STUDY OF 2012 INDIAN OCEAN EARTHQUAKES ON THAILAND’S

2018 ◽  
Author(s):  
Raya Muttarak ◽  
Wiraporn Pothisiri
Keyword(s):  
Indian Ocean ◽  
Emergency Preparedness ◽  
Disaster Preparedness ◽  
Formal Education ◽  
Disaster Experience ◽  
Individual Household ◽  
The Indian Ocean ◽  
The Individual

In this paper we investigate how well residents of the Andaman coast in Phang Nga province, Thailand, are prepared for earthquakes and tsunami. It is hypothesized that formal education can promote disaster preparedness because education enhances individual cognitive and learning skills, as well as access to information. A survey was conducted of 557 households in the areas that received tsunami warnings following the Indian Ocean earthquakes on 11 April 2012. Interviews were carried out during the period of numerous aftershocks, which put residents in the region on high alert. The respondents were asked what emergency preparedness measures they had taken following the 11 April earthquakes. Using the partial proportional odds model, the paper investigates determinants of personal disaster preparedness measured as the number of preparedness actions taken. Controlling for village effects, we find that formal education, measured at the individual, household, and community levels, has a positive relationship with taking preparedness measures. For the survey group without past disaster experience, the education level of household members is positively related to disaster preparedness. The findings also show that disaster related training is most effective for individuals with high educational attainment. Furthermore, living in a community with a higher proportion of women who have at least a secondary education increases the likelihood of disaster preparedness. In conclusion, we found that formal education can increase disaster preparedness and reduce vulnerability to natural hazards.

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