Measuring the influence of fibre-to-fabric properties on the pilling of wool fabrics

This study ranks the contribution of various fibre, yarn and fabric attributes to the pilling of wool knitwear. On the basis of an artificial neural network modelling, a combination of sensitivity analysis, forwards/backwards search and genetic algorithms was used to identify the importance of various fibre/yarn/fabric input parameters. The three different techniques show broad similarities in their assessment of which input parameters are important or are not important in affecting fabric pilling. The ranking shows that fabric cover factor has the most effect on pilling, followed by yarn count and thin places, fibre length, yarn twist, etc. It is further illustrated that the directional trend of the predicted pilling outputs for a selection of inputs was in line with the expected behaviour. To verify the findings of input feature selection, input factors deemed to have a small effect on the predicted pilling output, such as fibre length and diameter variations and curvature, were removed and the subsequent performance statistically compared to the original multi-layer perceptron. Differences between the outputs predicted by the original and pruned models are found not to be statistically significant at the 5% significance level. Results from this study may help manufacturers and knitwear designers in choosing the most appropriate materials and structures to reduce the pilling propensity of wool knitwear.

Modelling of fabric energy storage systems - a review

Fabric energy storage (FES) systems have gained in popularity in the recent years in response to the demand for energy efficient buildings. The dynamic heat transfer mechanisms of an FES require specialised techniques to predict its thermal performance. This requirement has been one of the barriers to the wider use of FES systems. Based on the research literature, this paper presents a critical review of the published mathematical models of FES systems. The paper discusses the usefulness of these models based on the following criteria: the inputs required; the accuracy of predictions; the ability to link with commercially available simulation software: and the degree of difficulty in using the models. The review found that the currently available mathematical models are either not able to predict the thermal behaviour of a building space with an FES system reliably or the models are too complicated and/or require too much specialised knowledge to make them useful.

Advanced fabric energy storage systems in Australia

There is a growing interest in the use of advanced fabric energy storage (FES) systems in Australia. The influence of slab thickness and ventilation rate on the annual thermal load, and maximum heating and cooling demands for an office module using a ventilated hollow core concrete slab system has been investigated by simulation. Airflow through the panels was set at 1, 2 or 4 air changes per hour (ACH) for slab thicknesses of 205, 220 and 300 mm. These configurations were simulated using two different FES operational strategies for six capital cities in mainland Australia. The simulations show that FES systems can offer either energy and/or peak load savings in almost all locations investigated. Overall, compared to a conventional AC system, the tempering of incoming fresh air combined with night flushing of the FES system appears to be the most successful operational strategy.

A controlled experiment on yarn hairiness and fabric pilling

This study focused on the hairiness of worsted wool yarns and how it affects the pilling propensity of knitted wool fabrics. Conventional worsted ring spun yarns were compared with comparable SolospunTM yarns and yarns modified with a hairiness reducing air nozzle in the winding process (JetWind). Measurements of yarn hairiness (S3) on the Zweigle G565 hairiness meter showed a reduction in the S3 value of approximately 46% was achieved using SolospunTM ring spinning attachment and a 33% reduction was achieved using the JetWind process. Interestingly, subsequent evaluation of the pilling performance of fabrics made from the SolospunTM spun yarn and JetWind modified yarn showed a half grade and full grade improvement, respectively over a similar fabric made from conventional ring spun yarns. This result suggested that a relatively large reduction in yarn hairiness was needed to achieve a moderate improvement in fabric pilling, and that the nature of yarn hairiness was also a key factor in influencing fabric pilling propensity. It is postulated that the wrapping of surface hairs by the air vortex in the JetWind process may limit the ability of those surface fibers to form fuzz and reach the critical height required for pill formation.

Influence of pH on hygral expansion, relaxation shrinkage and extensibility of wool fabric

The standard tests for relaxation shrinkage and hygral expansion of wool fabric take no account of pH. It is shown in this work that the pH of the solution in which wool fabric is relaxed as part of the procedure for measuring dimensional properties has a significant influence on the results. At around pH 4.8, which is close to the isoelectric point of wool, the hygral expansion reaches its greatest value and drops at both lower and higher pHs. A similar relationship between pH and extensibility of wool fabric was observed. Values of relaxation shrinkage were found to be dependant on pH. The reasons for the pH dependence of dimensional properties are discussed and these include changes in wool fiber swelling, yarn crimp and polymer relaxation phenomena with changes in pH.

Objective grading of fabric pilling with wavelet texture analysis

A new objective fabric pilling grading method based on wavelet texture analysis was developed. The new method created a complex texture feature vector based on the wavelet detail coefficients from all decomposition levels and horizontal, vertical and diagonal orientations, permitting a much richer and more complete representation of pilling texture in the image to be used as a basis for classification. Standard multi-factor classification techniques of principal components analysis and discriminant analysis were then used to classify the pilling samples into five pilling degrees. The preliminary investigation of the method was performed using standard pilling image sets of knitted, woven and non-woven fabrics. The results showed that this method could successfully evaluate the pilling intensity of knitted, woven and non-woven fabrics by selecting the suitable wavelet and associated analysis scale.

An experimental study on fabric softness evaluation

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.

Dependence of wool fabric dimensions on temperature and pH

Through a series of experimental analysis of temperature and pH value on the expansion of wool fiber and wool fabrics size change. In the pH2.1 solution, the wool fabric size declines with increasing temperature, changing the magnitude depends on the fabric and fabric shape rate. isoelectric point of pH4.8 in the wool, the fibers expand to reach the minimum, while the size of the fabric, along with the solution acidity increases.

Fabric of a dream: the Fletcher Jones story

This is the story of how a shell-shocked World War I veteran, who left school at 12, ended up building a national icon. An inspiring man with bold and imaginative ideas, Fletcher Jones was influenced by Japanese reformer Toyohiko Kagawa. Jones established his clothing design, retail and manufacturing business with emphasis on quality, service and innovation. But his primary concern was for people both his customers and his workers and they, in turn, were intensely loyal.

The effect of fabric strain during pressure steaming on fabric dimensional properties

It is shown that tension applied to fabric which is then permanently set by steaming under pressure for a short time has a significant effect on fabric dimensional properties. Increasing levels of stretch applied to fabric before pressure steaming resulted in decreases in fabric hygral expansion and relaxation shrinkage and also lowered fabric shrinkage that resulted from permanent setting. The setting conditions resembled those used in conventional pressure decatising, and it is suggested that in batch decatising, precise control of the length and width of fabric as it is batched up with the wrapper before steaming under pressure could enable predictable changes in fabric dimensions, relaxation shrinkage and hygral expansion to be obtained.

Small diameter Polyurethane vascular graft reinforced by elastic weft-knitted tubular fabric of polyester / spandex

Small diameter vascular grafts were fabricated from pure Polyurethane (PU) as well as PU reinforced with a tubular weft-knitted fabric. The tensile properties of the reinforced composite vascular grafts were compared with that of the tubular fabric itself and the pure PU vascular grafts. The elasticity and strength of the reinforced vascular grafts were improved compared with the tubular fabric. Strength of the reinforced vascular grafts was 5–10 times of the strength of the pure PU vascular grafts. Expanding the tubular fabric to increase the inner diameter of the reinforced vascular graft reduced the graft’s strength and initial modulus, but the difference was reduced as the PU content was increased. For grafts of the same inner diameter, increasing the PU content increased the thickness and strength of the graft wall, which led to a general increase in the strength and initial modulus of the composite vascular grafts.