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Open access

Vít Sháněl and Miroslav Španiel

Abstract

This paper details the numerical modeling of composite absorbers and an assessment of the influence of such deformation elements on a bus during frontal collision with a car. The absorber itself is designed as an assembly of thin-walled composite wound tubes oriented in the vehicle direction of travel. During the impact the tubes are crushed, causing energy absorption. Crash simulations were performed at various speeds using differing scenarios with the deformational member as well as without it. Comparative diagrams of force and velocity of the car and deformation of the bus structure were assessed

Open access

Piotr Lacki, Przemysław Kasza and Anna Derlatka

Abstract

The aim of the work was to perform numerical analysis of a steel-concrete composite floor located in a LIPSK type building. A numerical model of the analytically designed floor was performed. The floor was in a six-storey, retail and service building. The thickness of a prefabricated slab was 100 mm. The two-row, crisscrossed reinforcement of the slab was made from φ16 mm rods with a spacing of 150 x 200 mm. The span of the beams made of steel IPE 160 profiles was 6.00 m and they were spaced every 1.20 m. The steelconcrete composite was obtained using 80×16 Nelson fasteners. The numerical analysis was carried out using the ADINA System based on the Finite Element Method. The stresses and strains in the steel and concrete elements, the distribution of the forces in the reinforcement bars and cracking in concrete were evaluated. The FEM model was made from 3D-solid finite elements (IPE profile and concrete slab) and truss elements (reinforcement bars). The adopted steel material model takes into consideration the plastic state, while the adopted concrete material model takes into account material cracks.

Open access

Ondřej Bílek, Imrich Lukovics, David Sámek and Jana Knedlová

Abstract

Residual stresses lower the utility value of plastic parts. Determination of the induced stresses can help deal with them. Measurements are time-consuming and expensive. A new approach to measuring residual stresses, such as indentation measurement, can lead to the simple determination of residual stresses. The paper shows the relationship between the condition of injection moulding, the subsequent residual stress, and hardness through thickness. The computer model displays the field and magnitude of residual stress in the samples. The model results are then compared to measured parameters after indentation and the magnitude of residual stress determined by the standard hole drilling method.

Open access

Milan Sokol, Petra Velísková, Ľuboš Rehák and Martin Žabka

Abstract

The aim of the work is oriented towards the simulation or modeling of the lumbar and thoracic human spine as a load-bearing 3D system in a computer program (ANSYS). The human spine model includes a determination of the geometry based on X-ray pictures of frontal and lateral projections. For this reason, another computer code, BMPCOORDINATES, was developed as an aid to obtain the most precise and realistic model of the spine. Various positions, deformations, scoliosis, rotation and torsion can be modelled. Once the geometry is done, external loading on different spinal segments is entered; consequently, the response could be analysed. This can contribute a lot to medical practice as a tool for diagnoses, and developing implants or other artificial instruments for fixing the spine.

Open access

Martin Magura

Abstract

Gas pipelines pass through different topographies. Their stress level is influenced not only by gas pressure, but also by the adjacent soil, the thickness of any covering layers, and soil movements (sinking, landslides). The stress level may be unevenly spread over a pipe due to these causes. When evaluating experimental measurements, errors may occur. The value of the resistance reserve of steel can be adjusted by a detailed analysis of any loading. This reserve can be used in the assessment of a pipeline’s actual state or in reconstructions. A detailed analysis of such loading and its comparison with the simple theory of elasticity is shown in this article.

Open access

Mehdi Koohmishi

Abstract

In this paper, a comparison between pavement responses is performed by considering two different models for the linear viscoelastic behavior of an asphalt concrete layer. Two models, the Maxwell model and the Kelvin-Voigt model, are generalized. The former is used in ABAQUS and the latter in KENLAYER. As a preliminary step, an appropriate structural model for a flexible pavement structure is developed in ABAQUS by considering linear elastic behavior for all the layers. According to this model, when the depth of a structural model is equal to 6 meters, there is a good agreement between the ABAQUS and KENLAYER results. In this model, the thickness of the pavement is equal to 30 centimeters, and the thickness of the subgrade is equal to 5.7 meters. Then, the viscoelastic behavior is considered for the asphalt concrete layer, and the results from KENLAYER and ABAQUS are compared with each other. The results indicate that the type of viscoelastic model applied to an asphalt concrete layer has a significant effect on the prediction of pavement responses and, logically, the predicted performance of a pavement.

Open access

Henryk Olszewski, Wiktoria Wojnicz and Edmund Wittbrodt

Abstract

An original method of skeletal system modelling is presented in detail. Using DICOM images obtained from CT and PET tests, shell models of nine bones were created (humerus, radius, ulna, scapula, clavicle, femur, tibia, fibula, pelvis). Two methods of bone behaviour are also proposed, the first method treating the bone as a solid structure and the second method treating the bone as a complex porous structure. The behaviour of model parts is numerically examined by using the finite element method

Open access

T. Jankowiak and T. Łodygowski

Abstract

The paper considers the failure study of concrete structures loaded by the pressure wave due to detonation of an explosive material. In the paper two numerical methods are used and their efficiency and accuracy are compared. There are the Smoothed Particle Hydrodynamics (SPH) and the Finite Element Method (FEM). The numerical examples take into account the dynamic behaviour of concrete slab or a structure composed of two concrete slabs subjected to the blast impact coming from one side. The influence of reinforcement in the slab (1, 2 or 3 layers) is also presented and compared with a pure concrete one. The influence of mesh density for FEM and the influence of important parameters in SPH like a smoothing length or a particle distance on the quality of the results are discussed in the paper

Open access

W. Barnat

Abstract

This paper presents experimental and numerical studies on influence of an incidence angle of the shock wave on a steel plate. The problem of interaction between the wave front and a barrier is important from the point of view of protection the crew of armored vehicles. One way of remedying the harmful effects of impacts of the shock wave is the reflection wave of the barrier set at an angle to the face of the wave. The article presents the numerical and experimental approach to the subject. The numerical part presents four models in which the plate was set at angles 0◦, 15◦, 30◦, 45◦. In each case, the plate was loaded by a wave formed after the explosion 2 kg of TNT. In the experimental part the results are presented from an experiment in which the wave was formed from 2 kg TNT detonation at a distance of 0.4 m in parallel to the steel plate.

Open access

Björn Riemer and Kay Hameyer

Abstract

This paper presents a methodology for the calculation of the flux distribution in power transformer cores considering nonlinear material, with reduced computational effort. The calculation is based on a weak coupled multi-harmonic approach. The methodology can be applied to 2D and 3D Finite Element models. The decrease of the computational effort for the proposed approach is >90% compared to a time-stepping method at comparable accuracy. Furthermore, the approach offers a possibility for parallelisation to reduce the overall simulation time. The speed up of the parallelised simulations is nearly linear. The methodology is applied to a single-phase and a three-phase power transformer. Exemplary, the flux distribution for a capacitive load case is determined and the differences in the flux distribution obtained by a 2D and 3D FE model are pointed out. Deviations are significant, due to the fact, that the 2D FE model underestimates the stray fluxes. It is shown, that a 3D FE model of the transformer is required, if the nonlinearity of the core material has to be taken into account.