Jurčiová, Jana

Šuba, Oldřich

English

DSpace at VSB Technical University of Ostrava

lTINLIB�, Sborník vědeckých prací Vysoké školy báňské - Technické univerzity Ostrava číslo l, rok 2009, ročník LII, řada hutnická článek č. 1449 ON MECHANICAL DESIGN OF THERMOPLASTICALLY WELDED SHELL STRUCTURES 1 T. Bata University in Z/in; Faculty o/Technology, Z/ln, Czech Republic, suba@ft.utb.cz1 Faculty of Industrial Technolog/es; Alexander Dubček, University of Trenčín; Púchov, Slovak Republic,jurciova@lpt.tnuni.sk ABSTRACT: Some aspects of structural design of cylindrical thennoplastically welded containers are considered in the paper. · Implementations of welded thennoplastic shell vessels are connected by certain problems caused by generally insufficient flexura! stiffness of thennoplastic walls of thin­walled structures in.cases. of external backfill loads. As it is shown, low wall sti�ess causes not only high values of displacements, but predispositions it to the loss of stability of a construction at first. Influences of geometrical parameters and reinforcements ofthe shell structure on the level ofbuckling safety factor are studied with support ofFEM analyses. KEYWORDS: thermoplastic shells, reinforcement, buckling, FEM 1. INTRODUCTIONThermoplastics sink. into many industrial segments and pace of their applications is increasing. The reason for this is that ·c1assic materials do not fulfil the increasing technical needs. Without modem materials, series of innovating processes would not be peďormed. Specific properties of thermoplastics together with new processing and software technologies open wide possibilities of applications in variety of areas. Every successful application of thermoplastics is conditioned by consistent constructional and technological preparation, and also by qualified determination of dimensions and shapes of projected construction. Thermoplastics are in general less stiff and tough, and they have significant inclination to flow, high coefficient ofthermal expansion and significant dependence of mechanical properties on temperature. These properties are in general disadvantageous. On the other band, there are unquestionable positives - easy processing, low energetic demandingness and high productivity of manufacture or wide possibilities of new technologies. Not less important is also resistance to aggressive stuff and environments, which thermoplastics specialize for building of devices, working in hard conditions of operations, with an example in chemical and food industry. Specffication of thermoplastics mechanical behaviour includes specialities and problems in process of propose beside classical constructions. Technology character and effort of mass decreasing, price leads to a fact, that constructions of thermoplastics are mostly proposed as thin walled. Despite this fact, ratio of stiffness to strength is in thermoplastics greatly low, so in series of examples 1s the definitive state of deformation for product proposal not only carrying capacity. Definitive marginal states can often be for proposal, having eause in construction stability loss. 2. BŮCKLING RESISTANCE OF CYLINDRICAL SHELLSAn _example of important role of buckling resilience would be shells of small wastewater treatment vessels, sinks, cesspools etc. They are made of thin walled cylindrical shells with inner 102 

On mechanical design of thermoplastically welded shell structures

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On mechanical design of thermoplastically welded shell structures

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