Study of parameters affecting the strength of yarns

High velocity impact and armour design

“…The ballistic limit was again considerably below that of Dyneema. High performance fibre test results are generally available in the open literature, for example in [8,9]. These tests are normally conducted on fibres with yarns, typically 300 fibres or greater, hence the stress in calculated based on the number and crosssection area of these fibres.…”

“…A general form could be described by Equation (9) and can be expanded into incremental form to include a permanent or damage strain component. The magnitude of the permanent damage strain can be determined via the material constant '.…”

The effectiveness of combined gripping method in tensile testing of UHMWPE single yarn

“…The warp yarns were randomly extracted from the fabric with care for tensile testing. The bulk density and linear density of the yarn are 0.97 g/cm 3 and 1500 dtex respectively. The cross-sectional area of the yarn was calculated as 0.155 mm 2 by dividing the linear density of the yarn by its bulk density.…”

“…Previous study showed the tensile strength of a single Dyneema ® SK76 fibre exceeded that of a yarn by about 20% [2]. Furthermore, the strain rates observed in impact applications are far beyond the order of magnitude of the strain rates in the quasistatic loadings [3]. Hence, the material properties of constitutive single yarn must be studied under experimental conditions similar to impact events.…”

“…Although there is an increasing demand for characterising the tensile properties of high performance fibres, how to grip the fibres tightly enough without introducing excessive stress concentration is a challenging task. The principal requirements of a suitable gripping method are preventing fibre slippage while maintaining the fibre tension required to bring them to failure, and ensuring the failure occurs in the gauge section such that the failure is not initiated by the grips [3]. Several different methods for gripping fibres during tensile test were explored.…”