Estimating the creep strain to failure of PP at different load levels based on short term tests and Weibull characterization

Abstract

Abstract. The short and long term creep behavior is one of the most important properties of polymers used for engineering applications. In order to study this kind of behavior of PP tensile and short term creep measurements were performed and analyzed using long term creep behavior estimating method based on short term tensile and creep tests performed at room temperature, viscoelastic behavior, and variable transformations. Applying Weibull distribution based approximations for the measured curves predictions for the creep strain to failure depending on the creep load were determined and the parameters were found by fitting the measurements. The upper, mean, and lower estimations as well as the confidence interval for the means give a possibility for designers' calculations at arbitrary creep load levels.

A model for failure in thermoplastic elastomers based on Eyring kinetics and network connectivity

“…For a given applied stress at a fixed temperature, repeated simulations on equivalent samples produce a Weibull distribution of failure times P(t f ) [ Fig. 9(a)] [63][64][65][66], characterized by an average value s f and a shape parameter b,…”

Creep failure strain estimation of glass fibre/polypropylene composites based on short-term tests and Weibull characterisation

“…The method used for estimating the creep failure strain values at arbitrary load levels was developed and applied 18 to PP earlier.…”

“…In the case of real creep stimulus, 16,18 that contains the uploading process as well, the primary LVE response, 16 " L1 (t), estimation of the real creep curve and its Weibull-based distribution approximation 18 (see Figure 1 in Vas and Bakonyi 18 ) are as follows…”

“…16,17 This method was applied to estimate the tensile strength parameters and the creep failure strain of unreinforced polypropylene (PP) at arbitrary load levels, by making use of the information provided from tensile tests and short-term creep measurements as well as a Weibull-based distribution stochastic model. 18 In this article, this examination is extended for glass fibre (GF) reinforced PP composites.…”

Creep behaviour of injection-moulded basalt fibre reinforced poly(lactic acid) composites

“…However, to be able to use and design basalt fibre reinforced PLA composites in engineering applications, its long-term behaviour, especially its creep behaviour needs to be investigated, since thermoplastic polymer based composites are designed not to maximum allowable stress, but to maximum allowable strain. Bakonyi et al [31][32][33] extensively researched the creep of glass fibre reinforced Polypropylene (PP) and found that based on the temperature-time and loadtime superposition principle, long-term creep curves (mastercurves) could be constructed from short-term creep measurements. In a recent publication 34 the creep of PLA/bamboo fibre compression moulded composites was investigated by using temperature-time superposition principle.…”