Behaviour of Time-Dependent Materials under Periodical Mechanical Loading Conditions
This work presents the established methodology (theoretical model) that based on knowing the time-dependent behaviour of the materials enables durability prediction of periodically loaded time-dependent polymeric materials.
The main cause for the failure of periodically loaded polymeric materials are two different mechanisms that are both the consequence of their time-dependent behaviour; either this is the local overheating of the material, which results in drastic change in material’s mechanical properties and consequently leads to its failure, or the process of strain state accumulation occurs, which leads to the hardening of the material, crack formation and ultimately to the failure of the material.
The goal of the research work, elaborated in dissertation, was to upgrade and generalize theoretical approach for analysis of strain accumulation in periodically (cyclically) loaded drive belts. Developed methodology (strain accumulation approach) assumes certain type of loading conditions in terms of shear stress, and takes in consideration time-dependent behaviour of material, expressed with material retardation spectrum.
Applicability of proposed model is related to the upgrade of the measuring systems for characterization of time-dependent properties. As a first step this would be to incorporate algorithm for calculations of mechanical spectra and further on, to incorporate developed strain accumulation model for analysis of accumulation process.
Besides the information on the time-dependent properties (e.g., shear creep compliance,), experimental method would in this perspective also enable prediction of critical loading conditions that lead to the most intensive strain accumulation for a given material. Based on this analysis it would be possible to conclude, whether characterized material is appropriate for manufacturing of certain product considering the loading conditions, which the material would be exposed to.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
polymers, time-dependent behaviour, mechanical spectrum, periodical (cyclic) loading, drive belts, fatigue process, accumulation of the strain state, durability
Institute / chair: Faculty of Mechanical Engineering, University of Ljubljana
Technical consultant for expert services: Prof. Dr.-Ing. Igor Emri (Mentor), Prof. Dr.-Ing. Boris Stok, Asst. Prof. Dr. George Mejak, Prof. Dr. Crispulo Gallegos
Publication year: 2011
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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