P2-0264 — Annual report 2010
1.
Time-dependent behavior of ropes under impact loading : a dynamic analysis

In this paper, we present new methodology based on a simple, non-standard falling-weight experiment, which allows for the examination of the ropes properties beyond the findings from Union Internationale des Associations d'Alpinisme experiments. It is shown that the accuracy of prediction of all sought-after physical quantities could be obtained within the acceptable limits, which confirms that the proposed experimental-analytical methodology may be used for analyses of the functionality and durability of ropes and the safety of climbers.

COBISS.SI-ID: 10934299
2.
The effect of processing conditions on the durability of polymer products

The work discusses new possibilities of modifying the functionality of polymer products by changing their material structure during processing and consequently the time-dependent properties which define the durability of the final product. By analysing the low density polyethylene extrudates produced with a laboratory extruder, we observed that changing the processing conditions improves the durability of extrudates by several orders of magnitude. This opens new possibilities in the field of modifying the functionality of polymer products, and hence, better competitiveness on the world market.

COBISS.SI-ID: 11292955
3.
Time-dependent constitutive modeling of drive belts-2. The effect of the shape of material retardation spectrum on the strain accumulation process

This is the second paper in the series addressing the constitutive modeling of dynamically loaded elastomeric products such as power transmission belts. When the time-dependent properties of the elastomeric material “match” the time-scale of the dynamic loading a strain accumulation process occurs. It was shown that the location of a critical angular velocity, where the strain accumulation is the most intensive, strongly depends on the distribution of the retardation spectrum, whereas the magnitude of the accumulated strain is governed by the strength of the corresponding spectrum lines.

COBISS.SI-ID: 11241243
4.
The closed form t-T-P shifting (CFS) algorithm

Characterization of time- and/or frequency-dependent material properties usually requires shifting of the measured segments according to the Time-Temperature Superposition principle. This paper presents a closed form mathematical methodology (CFS) which completely removes ambiguity related to the manual shifting procedures. The derivation of the shifting algorithm is presented, and its validation using several simulated- and real- experimental data. It has been shown that error caused by shifting performed with CFS is at least 10–50 times smaller then the underlying experimental error.

COBISS.SI-ID: 11702043
5.
Time-dependent properties of bimodal POM - application in powder injection molding

Powder injection molding is applied for manufacturing complex and precise components from metal, ceramics or cemented carbide powder. It consists of mixing the powder and a polymeric binder, injecting this mixture in a mold, debinding and then sintering. Among the debinding techniques applied, catalytic debinding of polyoxymethylene (POM) stands out due to the high debinding rates and low risk of cracking. In this work, the potential use of a bimodal POM-based material as the main binder component was evaluated by comparing its thermal and time-dependent properties to a standard monomodal POM.

COBISS.SI-ID: 11702555