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The purpose of this paper is to make available to the parachute industry tools to predict behaviour of certain textile materials. In addition to this, it is desired to reveal and explain the basic requirement criteria for proper textile material selection. The strength of an assembly as a whole is directly dependent on the strengths of the various joints and seams required to assemble the larger structure. Keeping in mind the complex problem of parachute construction, this research seeks to enlighten the industry about the performance of seams in nylon woven canopy fabrics. Five factors have been studied: different types of weave (plain, rip-stop and twill), density (number of stitches per centimetre), different rows of stitches with lapped seams, different types of stitches (lock stitch, chain stitch and zig-zag) and seam direction (warp, weft and bias direction). Two responses have been analysed, the seam breaking force and the seam efficiency (per cent ratio of seam strength to fabric strength). The test results were subjected to an analysis of variance and the seam strength proved to vary significantly not only with the primary parameters, but with the interactions of the primary parameters as well. That is seam strength (and seam efficiency) changes with each primary parameter but it changes in a different manner when other parameters change. Multiple regressions have been used to construct preliminary predictor equations for seam strength and efficiency, and investigations to provide better equations are in progress.

ANOVA techniques and statistical regression equations were formed.

The work has concluded that twill weave 9 with chain stitch has the maximum seam strength, which makes canopies made with 2/1 twill weave and stitched with lapped seam with four rows of chain stitch optimum for heavy supply droppings with a single use parachute(s). It is evident from the results that twill weave with lock stich has the maximum seam efficiency. This makes the canopies stitched with twill fabric, constructed with lapped seams and four rows of stitches ideal for parachutes to be used multiple times. The brake parachutes on aircrafts and parachutes used by sky divers and air combat soldiers can use parachutes whose canopies can be used many times made out of the above mentioned weave and stitch specification.

Original work was conducted from the woven fabrics.

Parachutes are equipment that is repeatedly used as and when needed. Some of them are used for as many as 60 jumps. The property of the canopy fabric gets deteriorated with use. It is evaluated by destructive tensile and bursting strength. This study aims to focus on the nondestructive evaluation of the canopy fabric's fitness by testing air permeability and relating it with bursting strength. Predictor equations were developed to determine bursting strength from air permeability values.

ANOVA techniques and statistical regression equations were formed.

A series of samples containing five parachutes fabrics was used seven times, and their air permeability and bursting strength were determined to find the extent to the effect of reuse of parachute fabrics on their bursting strength and air permeability determination. It was found that there was a progressive drop in bursting strength and an increase in air permeability. An investigation of the extent of determination in terms of bursting strength and an increase in air permeability following the sense of five different types of parachute fabrics is reported.

The work focuses on the prediction of bursting strength to textile materials only and may not apply to other materials like membranes and sheets. The process of determining air permeability is relatively simpler and faster.

The bursting strength can be predicted for used parachutes, which are otherwise subjected to destructive testing.

The men using the parachutes can be assured of the superior flawless performance of the parachute as equipment and also contribute to the saving of resources due to nondestructive testing, 100% evaluation of all parachutes is possible.

This article describes the nature of the test procedure and discusses the means of introducing it to users of parachutes. It is accepted that the method must undergo field evaluation and possible modification before it can become a routine tool of parachute using organizations.