3.5.1: Material Properties
The component “MatProps” lets one directly define isotropic and orthotropic materials. Use the dropdown menu at the bottom of the component to chose between ortho- and isotropic materials.
Fig. 18.104.22.168: Definition of the properties of two isotropic materials via the “Material Properties” component
In Fig. 22.214.171.124 selection of the second material from the resulting list can be made (bottom right component) or selection from the default material table (top right component). Material isotropy means that the material’s behaviour does not change with direction. Karamba3D uses the following parameters to characterize an isotropic material (see fig. 126.96.36.199):
In case of temperature changes materials expand or shorten. “alphaT” sets the increase of strain per degree Celsius of an unrestrained element. For steel the value is
. Therefore an unrestrained steel rod of length
under an increase of temperature of
. “alphaT” enters calculations when temperature loads are present.
The utilization of cross sections as displayed by the “BeamView”-component (see section 3.6.7) is the ratio of actual stress and the tensile or compressive strength respectively. In case of shells, utilization is determined as the ratio of the result of the strength Hypotheses (as computed from the stresses in the shell) and the tensil or compressive strengh (see section 3.6.11).
Cross section optimization (see section 3.5.8) also makes use of the materials stength values. For reinforced concrete this may lead to excessive cross section thicknesses since concrete cross sections are handled as though being unreinforced. In order to get useful thickness values for reinforced conrete, one needs to scale up the concrete material's tensile strength.
Material orthotropy means that the material’s behaviour changes with direction. The material properties in two orthogonal directions fully characterize any orthotropic material. In Karamba3D orthotropic materials take effect only in shells. When supplied to beams, the material properties in the first direction are applied. For shells the first material direction corresponds to the local x-axis. See section 3.1.14 on how to set user defined local coordinate systems on shells.
Fig. 188.8.131.52: Definition of properties of an orthotropic material via the “Material Properties” component
In fig. 184.108.40.206 an orthotropic material gets defined using a “Material Property”-component. Besides “Family”, “Name”, “Elem|Id” and “Color” it expects the following input: