We presented the original approach developed at our research group for the numerical analysis of kinematically exact 3D beams where only the strains are assumed to be interpolated variables of the beam element. In contrast to traditional displacement-rotation based approaches, the additive-type of interpolation can be used without any restrictions. Another important characteristic of our approach is that the determination of internal forces and moments does not require the differentiation which increases the accuracy of stress field. This is of an utmost importance when dealing with materially non-linear problems.
B.04 Guest lecture
COBISS.SI-ID: 5970017We have been organizing the National Competition in Structural Mechanics for years. In 2012 the 18th competition was organized and the report with solutions was published. The competition has been prepared for pupils of several secondary schools in Slovenia with the main goal to increase the popularity of the field of structural mechanics and the increase of knowledge. The excellent response from pupils and their mentors has been experienced.
D.10 Educational activities
COBISS.SI-ID: 264712448This paper presents some results of the national research project "Strength grading of structural timber". Project is aimed to introducing the grading methods for softwood species (spruce, fir) into Slovenian sawmills and with the creation of an extensive database of the mechanical characteristics of sawn timber. The main objective of the project was a practical implementation of European standards into the production of sawn timber and to determine the correlations between the indicative properties of Slovenian timber and the grading characteristics. The relations of the national research project to the similar European research project "Gradewood (WP3 - Experimental research)", are also described in the paper.
F.10 Improvements to an existing technological process or technology
COBISS.SI-ID: 5917025A feasibility of using an ultrasonic wave reflection method (USWR) to evaluate microstructural changes during the early age hydration process of cement paste is presented. The method is materialized in a specially designed instrument ‘USWR-4 Hardening meter’. With the apparatus the changes in amplitude and phase shift of ultrasonic shear waves upon reflection can be measured in real time simultaneously and continuously during hydration from the first contact of cement with water. The reflection coefficient changes with time are related to the time growth of viscoelastic shear properties of the cement pastes. The method and the apparatus are very sensitive to parameters like a cement type, w/c ratio, temperature, the cement fineness and amount of C3A. A feasibility of using USWR method to estimate the initial and the final setting times is also demonstrated.
F.13 Development of new production methods and tools or processes
COBISS.SI-ID: 1028958In the present paper the displacement-based non-conforming quadrilateral affine thin plate bending finite element ARPQ4 is presented, derived directly from the non-conforming quadri- lateral thin plate bending finite element RPQ4 proposed by Wanji and Cheung. It is found, however, that the original element RPQ4 is only conditionally unisolvent. The newly derived element is shown to be inherently unisolvent. This convenient property results in the element ARPQ4 being more robust and thus better suited for computations than its predecessor. The convergence is mathematically proved and the rate of convergence estimated. The mathematically rigorous proof of convergence presented in the paper is based on Stummel’s generalized patch test and the consideration of the element approximability condition, which are both necessary and sufficient for convergence.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 5912929