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Article
Publication date: 1 March 2006

Peihua Zhang, Xin Liu, Lijing Wang and Xungai Wang

To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property.

Abstract

Purpose

To examine a simple testing method of measuring the force to pull a fabric through a series of parallel pins to determine the fabric softness property.

Design/methodology/approach

A testing system was setup for fabric pulling force measurements and the testing parameters were experimentally determined. The specific pulling forces were compared with the fabric assurance by simple testing (FAST) parameters and subjective softness ranking. Their correlations were also statistically analyzed.

Findings

The fabric pulling force reflects the physical and surface properties of the fabrics measured by the FAST instrument and its ability to rank fabric softness appears to be close to the human hand response on fabric softness. The pulling force method can also distinguish the difference of fabrics knitted with different wool fiber contents.

Research limitations/implications

Only 21 woven and three knitted fabrics were used for this investigation. More fabrics with different structures and finishes may be evaluated before the testing method can be put in practice.

Practical implications

The testing method could be used for objective assessment of fabric softness.

Originality/value

The testing method reported in this paper is a new concept in fabric softness measurement. It can provide objective specifications for fabric softness, thus should be valuable to fabric community.

Details

International Journal of Clothing Science and Technology, vol. 18 no. 2
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 25 February 2014

Kadir Bilisik and Bekir Yildirim

– The aim of this study was to understand the stick-slip properties of single and multiple yarn pull-out in dry and treated polyester satin woven fabric in boundary regions.

Abstract

Purpose

The aim of this study was to understand the stick-slip properties of single and multiple yarn pull-out in dry and treated polyester satin woven fabric in boundary regions.

Design/methodology/approach

Polyester satin pattern woven fabric was used to conduct the pull-out tests in order to examining the kinetic region of the force-displacement curve. Data generated from this research help the authors to obtain stick-slip force and accumulative retraction force.

Findings

It was found that stick-slip force and accumulative retraction force depend on the number of pulled ends in the fabric, fabric sample dimensions and softening treatments. Stick-slip forces of polyester satin fabric in the multiple yarn pull-out test were higher than those of the single yarn pull-out test. Stick-slip force in single and multiple yarn pull-out tests in the dry polyester satin fabric was generally higher than those of the softening treated polyester satin fabric. In addition, the warp directional single and multiple yarn stick-slip and accumulative retraction forces in the dry and softening treated polyester fabrics were generally higher than those in the weft direction in the fabric edges due to fabric density. On the other hand, the amount of stick-slip force was related to the number of interlacement points in the fabric, whereas the amount of accumulative retraction force was related to fabric structural response.

Originality/value

The mechanism of stick-slip and accumulative retraction force of dry-treated polyester satin pattern woven fabrics were explained. This research could be valuable for development of multifunctional fabrics in technical textiles and ballistic.

Details

International Journal of Clothing Science and Technology, vol. 26 no. 1
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 31 May 2019

Kehang Yu, Chen Yang, Jun Wang, Jiabo Yu and Yi Yang

The purpose of this paper is to study the variation of the mechanical strength and failure modes of solder balls with reducing diameters under conditions of multiple reflows.

Abstract

Purpose

The purpose of this paper is to study the variation of the mechanical strength and failure modes of solder balls with reducing diameters under conditions of multiple reflows.

Design/methodology/approach

The solder balls with diameters from 250 to 760 µm were mounted on the copper-clad laminate by 1-5 reflows. The strength of the solder balls was tested by the single ball shear test and pull test, respectively. The failure modes of tested samples were identified by combing morphologies of fracture surfaces and force-displacement curves. The stresses were revealed and the failure explanations were assisted by the finite element analysis for the shear test of single solder ball.

Findings

The average strength of a smaller solder ball (e.g. 250 µm in diameter) is higher than that of a larger one (e.g. 760 µm in diameter). The strength of smaller solder balls is more highly variable with multiple reflows than larger diameters balls, where the strength increased mostly with the number of reflows. According to load-displacement curves or fracture surface morphologies, the failure modes of solder ball in the shear and pull tests can be categorized into three kinds.

Originality/value

The strength of solder balls will not deteriorate when the diameter of solder ball is decreased with a reflow, but a smaller solder ball has a higher failure risk after multiple reflows. The failure modes for shear and pull tests can be identified quickly by the combination of force-displacement curves and the morphologies of fracture surfaces.

Details

Soldering & Surface Mount Technology, vol. 31 no. 4
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 January 1992

N. Brady and T.J. Ennis

Tensile pull strength tests were used to study the strength of solder joints of 25 mil gull wing leads on 132 pin quad flat pack components. The authors generated…

Abstract

Tensile pull strength tests were used to study the strength of solder joints of 25 mil gull wing leads on 132 pin quad flat pack components. The authors generated quadratic and linear models which can be used to predict the pull strength of a solder joint given its geometry. The shape parameters studied were stand‐off height between the lead and substrate, height of heel fillet, radius of curvature of heel fillet, length of heel fillet, height of solder at toe region, and thickness of solder on the lead. The most significant parameters in determining the tensile pull strength of the solder joint are the height and length of the heel fillet. A study was performed to quantify the effect of lead finish on the accuracy of these models. The lead finish was found to have a significant effect on the solder joint strength. The effect of lateral misregistration on the tensile pull strength of solder joints was also investigated. No correlation between the extent of lateral misregistration and joint pull strength has been found.

Details

Soldering & Surface Mount Technology, vol. 4 no. 1
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 1 April 1989

T.C. Chung and H.A. Moore

Tape automated bonding (TAB) is one technology which is becoming widely adopted for interconnecting integrated circuits to a substrate or package. Both destructive and…

Abstract

Tape automated bonding (TAB) is one technology which is becoming widely adopted for interconnecting integrated circuits to a substrate or package. Both destructive and non‐destructive test methods for evaluation of TAB bonds are analysed and criticised. The key parameters and general guidelines of a destructive beampull test set‐up are identified and presented. The key features of four different non‐destructive test methods are described and discussed. It is found that no universal solution exists for non‐destructive evaluation of TAB bonds although some methods may be more useful than others under certain conditions and constraints. Data and experimental procedure are presented for correlation of scanning laser acoustic microscopy and beampull data.

Details

Circuit World, vol. 16 no. 1
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 9 November 2010

A.E. Richardson, K. Coventry and S. Landless

Establishing toughness performance in concrete using steel fibres is well understood, and design guides are available to assist with this process. What is less readily…

Abstract

Purpose

Establishing toughness performance in concrete using steel fibres is well understood, and design guides are available to assist with this process. What is less readily understood is the use of Type 2 synthetic fibres to provide toughness. This problem is exacerbated by the wide range of synthetic fibres available, with each different fibre providing different structural properties. This paper seeks to address this issue.

Design/methodology/approach

The paper examines the relative pull‐out values of two single fibre types, i.e. steel and Type 2 synthetic fibres. The pull‐out test results have informed the doses of fibre additions to beams which have been used to equate near equal toughness performance for each fibre type.

Findings

The results show that synthetic Type 2 fibres, when used at a prescribed additional volume, can provide toughness equal to steel fibre concrete.

Originality/value

The scientific study of fibre pull‐out behaviour is well understood and described herein under additional reading. Practical testing to show contractors and clients how to balance the dose of fibres in concrete, so that synthetic fibres could be used as a steel fibre replacement, is not well researched. This paper bridges the information gap.

Details

Structural Survey, vol. 28 no. 5
Type: Research Article
ISSN: 0263-080X

Keywords

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Article
Publication date: 23 March 2020

Hongchang Wang, Cheng Jin, Houyu Liu and Zhiqiang Xue

As an important part of steel bridge deck pavement, if waterproof adhesive layer performance does not meet requirements, numerous kinds of bridge deck pavement distress…

Abstract

Purpose

As an important part of steel bridge deck pavement, if waterproof adhesive layer performance does not meet requirements, numerous kinds of bridge deck pavement distress may be encountered. To study the adhesive behavior of rubber asphalt waterproof adhesive layers in steel bridge gussasphalt pavement, the pull-off and direct-shear tests have been used in the study to mechanically simulate steel bridge deck pavement under vehicles loading.

Design/methodology/approach

Several potentially influential factors associated with the adhesive strength of rubber asphalt are investigated including temperature, spraying quantity and environmental conditions.

Findings

Results indicate that rubber asphalt was associated with good performance with respect to its use as a waterproof adhesive layer; simulated performance was negatively correlated with increasing temperatures. A necessary spraying quantity of 0.4 Lm-2 is required for appropriate adhesive strength of the composite structure, with a decrease in adhesive strength noted when spraying quantity is significantly greater or less than this.

Originality/value

The current paper presents an examination of the adhesive performance of a rubber asphalt adhesive layer on steel bridge deck pouring construction, while additionally examining potentially influential factors and conditions via use of both pull-off and shear tests.

Details

International Journal of Structural Integrity, vol. 12 no. 2
Type: Research Article
ISSN: 1757-9864

Keywords

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Article
Publication date: 11 April 2008

Jeffery C.C. Lo, B.F. Jia, Z. Liu, J. Zhu and S.W. Ricky Lee

The purpose of this paper is to evaluate the lead‐free solder joint reliability of a variety of surface mount components assembled onto printed circuit boards (PCBs) under…

Abstract

Purpose

The purpose of this paper is to evaluate the lead‐free solder joint reliability of a variety of surface mount components assembled onto printed circuit boards (PCBs) under a number of different tests.

Design/methodology/approach

Lead‐free solder with a composition of Sn96.5‐Ag3.0‐Cu0.5 was used in a surface mount reflow process. Different types of surface mount dummy components with a daisy chain, such as CBGAs, BGAs, PLCCs, CSPs, and QFNs, were assembled onto PCBs. Both the mechanical and thermo‐mechanical reliability of the solder joints were evaluated by several tests. The experiments included package shear, package pull, three‐point bending and accelerated thermal cycling testing for 2,000 cycles. The packages were examined by X‐ray and C‐SAM before the reliability tests were carried out. The maximum load and the corresponding load‐displacement curve were recorded in the mechanical test.

Findings

The results from the mechanical tests show the major failure mode is on the copper pad. Weibull analysis shows that the characteristic lives of most packages are between 1,100 and 2,400 cycles. For the CBGA, the characteristic life of 96 cycles is relatively short, due to the serious CTE mismatch. Cross‐section inspection shows failures occur at the solder joint. Copper pad failure is also observed.

Originality/value

This paper provides both the mechanical and thermal‐mechanical reliability of lead‐free solder joints. The experimental data are very useful in the lead‐free SMT industries.

Details

Soldering & Surface Mount Technology, vol. 20 no. 2
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 4 November 2014

Mica Grujicic, Jennifer Snipes, S. Ramaswami and Fadi Abu-Farha

The purpose of this paper is to propose a computational approach in order to help establish the effect of various self-piercing rivet (SPR) process and material parameters…

Abstract

Purpose

The purpose of this paper is to propose a computational approach in order to help establish the effect of various self-piercing rivet (SPR) process and material parameters on the quality and the mechanical performance of the resulting SPR joints.

Design/methodology/approach

Toward that end, a sequence of three distinct computational analyses is developed. These analyses include: (a) finite-element modeling and simulations of the SPR process; (b) determination of the mechanical properties of the resulting SPR joints through the use of three-dimensional, continuum finite-element-based numerical simulations of various mechanical tests performed on the SPR joints; and (c) determination, parameterization and validation of the constitutive relations for the simplified SPR connectors, using the results obtained in (b) and the available experimental results. The availability of such connectors is mandatory in large-scale computational analyses of whole-vehicle crash or even in simulations of vehicle component manufacturing, e.g. car-body electro-coat paint-baking process. In such simulations, explicit three-dimensional representation of all SPR joints is associated with a prohibitive computational cost.

Findings

It is found that the approach developed in the present work can be used, within an engineering optimization procedure, to adjust the SPR process and material parameters (design variables) in order to obtain a desired combination of the SPR-joint mechanical properties (objective function).

Originality/value

To the authors’ knowledge, the present work is the first public-domain report of the comprehensive modeling and simulations including: self-piercing process; virtual mechanical testing of the SPR joints; and derivation of the constitutive relations for the SPR connector elements.

Details

Multidiscipline Modeling in Materials and Structures, vol. 10 no. 4
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 March 1993

J. Liu

The purpose of the work is to investigate the feasibility of using anisotropically conductive adhesives to join surface‐mount devices as solder replacement. The results…

Abstract

The purpose of the work is to investigate the feasibility of using anisotropically conductive adhesives to join surface‐mount devices as solder replacement. The results from a literature and market survey are reported. Based on industrial demands, two anisotropically conductive adhesives were chosen for the experimental work. During the experimental work, the conductive adhesive joints were produced at various curing conditions. The joints were characterised by shear testing and electrical resistance measurement after ageing at 20, 70 and 120°C to 1000 hours. Optical and scanning electron microscopy were used to characterise the adhesive joints. In addition to this, temperature cycling tests, humidity test and pull tensile tests were used to qualify the adhesive joint reliability and quality. From the results of the present work, it can be concluded that the anisotropically conductive adhesive A joints are stable in the 85°C/85% RH environment and therefore have better corrosion resistance than adhesive B joints. Neither of the adhesives can pass temperature cycling from −55 to 125°C for 1000 cycles according to military standard 883C.

Details

Circuit World, vol. 19 no. 4
Type: Research Article
ISSN: 0305-6120

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