653 Study on Fracture Toughness Calculation by Single Specimen of High Polymer Materials

Many design scenarios of components made of polymer materials are concerned with notches as representative constructive details. The failure hazard assessment of these components using models based on the assumption of cracked components leads to over-conservative failure estimations. Among the different alternative approaches proposed that are based on the apparent fracture toughness, KcN is considered. In so doing, the current deterministic underlying concept must be replaced by a probabilistic one to take into account the variability observed in the failure results in order to ensure a reliable design. In this paper, an approach based on the critical distance principle is proposed for the failure assessment of notched EPOLAM 2025 CT samples with each different notch radii (ρ) including a probabilistic assessment of the failure prediction. First, each apparent fracture toughness is transformed into the equivalent fracture toughness for ρ=0 based on the critical distances theory. Then, once all results are normalized to the same basic conditions, a Weibull cumulative distribution function is fitted, allowing the probability of failure to be predicted for different notch radii. In this way, the total number of the specimens tested in the experimental campaign is reduced, whereas the reliability of the material characterization improves. Finally, the applicability of the proposed methodology is illustrated by an example using the own experimental campaign performed on EPOLAM 2025 CT specimens with different notch radii (ρ).

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Influence of the pressure of the ambient medium upon the volume of high-polymer materials

Journal of Engineering Physics ◽

10.1007/bf00826228 ◽

1970 ◽

Vol 19 (3) ◽

pp. 1067-1071

Author(s):

M. Rainer ◽

R. Taxerman-Croser

Keyword(s):

Ambient Medium ◽

Polymer Materials ◽

High Polymer

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Hypotheses about the Tools Origin of Textile Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1090.18 ◽

2015 ◽

Vol 1090 ◽

pp. 18-21

Author(s):

Yuan Tao ◽

Wei Dong Yu

Keyword(s):

Soft Materials ◽

Stone Tools ◽

Polymer Materials ◽

Evidence Based ◽

High Polymer ◽

Origin Time ◽

Textile Materials ◽

Physical Evidence ◽

Better Than

As high polymer materials, textile materials are easily to be carbonized and then disappear, so it is almost impossible to study the origin of it from physical evidence. Based on the objective historical facts, through analysis and inference, the paper believed that textile materials, as soft materials, are better than stone tools in the aspects of obtaining, making, functions and uses. Two hypotheses about the origin of textile materials are proposed. The first is that textile materials originate from tools, and the origin time of it is not later than stone tools. The second is that signs and clothing application of textile materials both evolve from its usage as tools, so the origin sequence of textile materials is tools, signs, and clothing.

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