Seam Performance Research Articles

Kumaş Kat Sayısının İğne Batış Kuvvetine Etkisinin İncelenmesi

In this study, it is aimed to investigate the effects of fabric ply numbers to the seam performance specially sewing needle penetration forces. Therefore, four fabric samples having different specifications were obtained and these fabrics were sewn with one, two, three and four plies. Sewing needle penetration forces were determined for these fabric plies. At the end of the study, it has been shown that at fabric seams when fabric ply number increased, sewing needle penetration forces also increased and fabric yarns were damaged more quickly by the needle which have high penetration force

Manufacturing and Sewing Performance of Polyurethane and Polyurethane/Silicone Coated Fabrics

In this research, polyurethane (PU) and polyurethane/silicone (PU/silicone) coated fabrics were manufactured and the effects of coating parameters such as coating material, coating technique, and production parameters on sewing performance of the coated fabrics were investigated. During manufacturing processes, one fabric sample having cotton as raw material and having plain weave was used as the base fabric. The base fabric was coated with two coating materials as PU and PU/silicone by two coating techniques such as rotary screen coating and blade coating with systematically changing production parameters (screen pressure and contact angle). Therefore, twelve coated fabric samples having different technical specifications were produced. Due to the limited number of studies in related literature, sewing performance of the coated fabrics was investigated by the tensile properties of the unsewn and the sewn fabrics and also the seam efficiency values were compared. Variance analyses were used to determine and evaluate the effects of coating parameters on seam performance of the coated fabrics.

Towards Predictive Control of Extrusion Weld Seams: An Integrated Approach

Longitudinal weld seams are an intrinsic feature in hollow extrusions produced with porthole dies. The formation of longitudinal weld seams is a solid bonding process, controlled by the local conditions in the extrusion die. Being the weakest areas within the extrusion cross section, it is desirable to achieve adequate properties of these weld seams. In our research, the concept of a weld seam integrity indicator as a means of quantifying bonding efficiency is introduced. The value of this indicator depends on a number of factors: the material flow within the die weld chambers, an adequate pressure level acting on the weld planes and finally the evolution of the metal microstructure. Optimisation of the welding conditions leads to a higher value of the weld seam integrity indicator and thus to improved weld seam properties. The objective of the research presented in this paper is to assess the feasibility of this concept. In lab-scale experiments, AA6060 and AA6082 aluminium alloy billets were formed into strips by means of the direct hot extrusion process. By utilising porthole dies a central longitudinal weld seam is formed. The effect of different geometries of the weld chamber and the processing conditions on the quality of the weld seam are investigated. Characterisation of these weld seams through mechanical testing, focusing on the ability of the weld seam area to accommodate plastic deformation following the onset of plastic instability, and microstructural analysis provides insight into bonding performance. The outcome of this characterisation provides a basis for an estimation of the weld seam indicator. Through computer modelling, the particular process conditions related to weld seam formation are calculated and correlated with the experimental results. The experimental results clearly demonstrate that weld seam formation is controlled by a combination of factors as described above. Inadequate fulfilment of these conditions, verified by the FE-simulations, is the cause of inferior weld seams, associated with low values of the weld seam integrity indicator. Through further elaboration of the concepts presented in this work, the weld seam integrity indicator is to be developed, with the future aim of predicting the weld seam performance through finite element simulations.

Predicting Seam Performance of Commercial Woven Fabrics Using Multiple Logarithm Regression and Artificial Neural Networks

In this study, the capability of artificial neural networks and multiple logarithm regression methods for modeling seam performance of commercial woven fabrics based on seam puckering, seam flotation and seam efficiency were investigated. The developed models were assessed by verifying Mean Square Error (MSE) and Correlation Coefficient ( R-value) of test data prediction. The results indicated that the artificial neural network (ANN) model has better performance in comparison with the multiple logarithm regression model. The difference between the mean square error of predicting in these two models for predicting seam puckering, seam flotation, and seam efficiency was 0.0394, 0.0096, and 0.0049, respectively. Thus, the ANN model was found to be more accurate than MLR, and the prediction errors of ANNs was low despite the availability of only a small training data set. However, the difference in prediction errors made by both models was not significantly high. It was found that MLR models were quicker to construct, more transparent, and less likely to overfit the minimal amount of data available. Therefore, both models were effectively predicting the seam performance of woven fabrics.

Investigation of the Seam Performance of PET/Nylon-elastane Woven Fabrics

This paper presents an experimental study of the seam performance of PET/nylon-elastane woven fabrics. In this study, plain and twill fabrics were woven with three different weft densities. Two different sewing threads were used during the sewing of the fabrics. Therefore, 12 samples having different specifications were obtained. For these fabrics, nylon-elastane air-covered yarn was used as the weft yarn and PET air-covered yarn was used as the warp yarn. Seam strength, seam slippage strength, sewing needle penetration force and seam efficiency were determined for these fabrics for seam performance. The purpose of this study was to identify the suitable sewing conditions in order to achieve good seam performance. This study also investigated the effects of weft density, weave type and sewing thread on the seam performance.

Sewing Needle Penetration Forces and Elastane Fiber Damage during the Sewing of Cotton/Elastane Woven Fabrics

This paper presents an experimental study of the effects of elastane draw ratio, pre-setting temperature and finishing process on the penetration forces of a sewing needle and damage to the elastane fibre during the sewing of cotton/elastane woven fabrics. Seam strength and seam opening strength of the fabrics were also determined for assessment of seam performance. In this study three fabric types with three different elastane weft yarn draw ratios were taken as samples for the experiments. As the first step a pre-setting process was applied to all three types of fabric at two different temperatures and at the finishing process half of the samples were treated with silicone and the other half were washed only. In total, 12 samples having different specifications were obtained. For these fabrics, nylon/elastane air-covered yarn was used as the weft yarn and cotton yarn as the warp yarn. Seam strength, seam opening strength, needle penetration forces and “needle damage index” were determined for these fabric samples. The needle penetration forces were between 100 and 140 cN and the “needle damage index” values were between 20 and 42%. Photographs were taken with an optical microscope and a scanning electron microscope to show the elastane fiber damage during the sewing.

Characterization of polymer modified bituminous roofing membranes using thermal analysis

The thermal properties influencing seam performance of polymer modified bituminous roofing membranes are investigated using thermogravimetry and differential scanning calorimetry. Ten different commercial roofing materials are included: three atactic polypropylene (APP) modified bitumens and seven styrene-butadiene-styrene copolymer (SBS) modified bitumens. The results show that the difference in specific heat among different SBS or APP products was small. However, the specific heat of APP products was approximately 0.2 J g−1 K−1 higher than that of SBS products. It may indicate that for APP products a higher amount of energy is required for welding. Overheating of the membranes above 200°C during heat welding may cause decomposition in the polymer modified bitumen, since the degradation of pyrolysable organics begins at ∼200°C.

Characterization of polymer modified bituminous roofing membranes using chromatography

This is part of a broad study to characterize polymer modified bituminous roofing materials studied for seam performance. Ten different commercial roofing materials, three of atactic polypropylene (APP) modified bitumen and seven of styrene-butadine-styrene copolymer (SBS) modified bitumen, were studied using high performance liquid chromatography for the analysis of the original bitumen binders and high performance gel permeation chromatography for the qualitative and quantitative analysis of the polymers. The results show that the oxidized bitumen has the highest asphaltene content at about 30%. The asphaltene content of the original bitumen in APP products is higher than in SBS products. The difference in the amount of polymer in each product is not great, and no correlation with seam strength is observed. The degradation of the polymer, which refers to the decrease in molecular weight or the increase in molecular weight distribution can be identified.

Destructive testing of polyethylene geomembrane seams: Various methods to evaluate seam strength

The incidence of high-density polyethylene geomembrane liner failures makes it essential that as much information as possible regarding seam performance be extracted from testing. The durability of polyethylene geomembrane seams can be determined largely by the data resulting from conventional seam peel and shear destructive tests. Unfortunately, current test parameters and acceptance criteria are not used to a great enough extent. Specifically, the seam peel and shear tests can and should be used more fully to assess the effect of seaming on the strength and durability of the seam and the adjacent geomembrane. Specific minimum values for seam shear strength and elongation as well as peel separation should be established by a project's geosynthetic design engineer. In addition, functional seam test acceptance criteria for very low-density polyethylene need to be defined. Another type of testing that can provide valuable information on the aging behavior and defect distribution within field seams is hydrostatic, biaxial burst testing.