Új rugalmas fenomenológiai anyagtörvény műszaki textíliákhoz

Hegyi, Dezső and Sajtos, István (2009) Új rugalmas fenomenológiai anyagtörvény műszaki textíliákhoz. Építés - Építészettudomány, 37 (1-2). pp. 95-106. ISSN 0013-9661

Text eptud.37.2009.1-2.4.pdf Restricted to Repository staff only until 31 March 2029. Download (732kB)

Abstract

Új anyagtörvény kerül bemutatásra, mely fenomenológiai módon írja le műszaki textíliák feszültség-megnyúlás viselkedését. Az anyagmodell figyelembe veszi a műszaki textíliák két szálirányának kölcsönhatását. | Traditionally linear elastic material law is used for textile membrane structures in the analysis. The capacity of the old computers was too small to deal with the complex material law together with the highly nonlinear analysis of the structure. In the last decade high number of papers were published about nonlinear material laws according to the elastic and time dependent deformations. It is well known, that the characteristic of the material law of a technical textile is highly nonlinear like the analysis of the structure. There are two reasons: the nonlinear material law of the elements (the yarns and the matrix) and the geometric nonlinearity of the yarns. One way to handle the problem of the nonlinear material law is to use a micro model. In the micro model they build up the internal geometry of the material with the properties of the elements and the connections. It is very famous today, but it needs too much input data for the practice. The usage of a phenomenology material law can be more suitable than a micro model. In a phenomenology model we ignore what happens inside the material law. We use a function to describe the behavior of the material. There are methods with phenomenology material laws, but they neglect the interaction of the two yarn direction or they cannot extrapolate the material law over the measured data. The new phenomenology material law in this paper uses exponential functions. These functions converge to a monotone increasing line. It means that it can approximate a reasonable stress value over the measured data, even if the strain is unrealistic. It is an important feature in a highly nonlinear calculation, where during the iteration we can have extreme deformations. The new model can represent the interaction of the yarns of the two directions. For the usage of the new material law we need the stress-strain data of the material. To represent the interaction of the two yarn directions both (parallel and perpendicular) strain values are needed for each load level, and the best is to get bi-directional test data. The exponential functions of the new material law are not simple, but in computer software it is not a problem. The functions can give back the stress level for each strain pair (according to the yarn directions) very fast and very effectively.

Actions (login required)

Edit Item