Applied Mechanics and Materials Vol. 769

Abstract: The paper deals with an issue of strengthening of damaged RC beams by a coupling slab. Within the experimental programme, the non-strengthened beams had been first loaded up to the level 0.7, consequently were strengthened by an overconcreted slab and loaded up to the failure. The mutual coupling was performed by different techniques. We complete obtained results of tests of an influence of a contact type of a repaired beam and a slab on a resistance, serviceability characteristics and a failure mode of a resultant strengthened element. The experimental results are compared, and thus serve as their verification, with designed values of resistance determined according to the corresponding standard and also with results of numerical simulations performed using the commercial software ATENA.

Abstract: Thermo-steel panels compose from steel thin-walled profiles and polystyrene. They are used as wall construction elements. We must follow stability problems. Finite strip method (FSM) has been used. Special arrangement had to be done for investigation of stability of thermo-steel panels. In thermo-steel panels compression stresses are carried in thin-walled steel profiles only. It means that polystyrene enter into stiffness matrix but it does not have increment in geometric matrix. Numerical examples were oriented for investigation of thermo-steel panels with 145 and 250 mm thickness. Obtained results proved ability of thermo-steel panel to be used as wall panel for two storey building.

Abstract: Concrete is a traditionally used building material and its crack resistance can be improved by the addition of different types of fibres. Wedge splitting tests on specimens fabricated from five types of concrete mixture (six identical specimens from each mixture) were used to quantify the mechanical fracture parameters of these materials – a reference specimen without fibres, two others with steel fibres (Dramix, Tabix), and a final two with synthetic fibres (Enduro, Strux). Vertical load versus crack mouth opening displacement (P–CMOD) diagrams were recorded during the tests. The data points creating these diagrams were filtered first, subsequently processed and then evaluated using the double-K fracture model. Thus, values were obtained for e.g. Young’s modulus and fracture toughness. This paper is focused on quantification of the effect of the fibre type used in concrete on crack initiation, which corresponds to the beginning of stable crack growth in this sort of composite material.

Abstract: The hygrothermal effect is introduced by using empirical relations for degrading the material stiffness properties of the matrix. A parametric study is conducted by varying the fiber volume fraction and the fiber orientation of the angle plies in the laminate. It is possible to minimize the environmental effect by judiciously selecting the laminate configuration.

Abstract: Laminated glass has been developed to improve the impact resistance of brittle glass sheets and to prevent injuries and collapse of glass members. The goal of this contribution is to briefly introduce a finite element model based on the refined plate theory by Mau that can describe the response of laminated glass plates without the need for fully resolved three-dimensional simulations. Each layer is considered to behave according to the Reissner-Mindlin kinematics, complemented with membrane effects and the von Karman assumptions. The compatibility of independent layers is enforced by nodal Lagrange multipliers. Predictions of the finite element model, obtained with a MATLAB-based program LaPla (Laminated Plates) developed by the authors, are compared with simplified monolithic and layered limits and a semi-analytical solution.

Abstract: The article deals with the modelling of composite structures by means of the ABAQUS software application. This numerical modelling is based on the results obtained from measurements on a series of experimental models. It defines the contacts between concrete, steel and concrete reinforcement. The required accuracy of theoretical solutions will be guaranteed by the appropriate depiction of contacts between different materials. Creating adequate procedures for the design of composite structures will be possible due to the application of established and well-proven theoretical models.

Abstract: Fiber reinforced concrete is composite material containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. This paper deals with a comparison of both models made of reinforced concrete and fiber reinforced concrete as well as their optimization. The problem was modeled in ANSYS program. Some results of optimal design are presented at the end of this paper.

Abstract: The paper compares the numerical models of and experiments with a beam. The purpose is to evaluate the nonlinear material model of a steel structure. The steel is modelled as an ideal elastic-plastic material. The FEM and eight-node isoparametric finite elements are considered in the analysis. The 3D calculations use different material constants and several approaches are being tested in order to create the computational models. The calculations are performed in the software application developed by our university.