The aim of this paper is to investigate and compare the stress distribution of a reconstructed pelvis under different screw forces in a typical walking pattern. Computer-aided design models of the pelvic bones and sacrum made based on computer tomography images and individually designed implants are the basis for creating finite element models, which are imported into ABAQUS software. The screws provide compression loading and bring the implant and pelvic bones together. The sacrum is fixed at the level of the L5 vertebrae. The variants of strength analyses are carried out with four different screw pretension forces. The loads equivalent to the hip joint reaction forces arising during moderate walking are applied to reference points based on the centres of the acetabulum. According to the results of the performed analyses, the optimal and critical values of screw forces are estimated for the current model. The highest stresses among all the models occurred in the screws and implant. As soon as the screw force increases up to the ultimate value, the bone tissue might be locally destroyed. The results prove that the developed implant design with optimal screw pretension forces should have good biomechanical characteristics.

This study presents a model for Ti6Al4V alloy produced by applying electron beam melting as continuum media with orthotropic elastic and plastic properties and its application in total hip replacement (THR). The model exhibits three Young’s moduli, three shear moduli, and three Poisson’s ratios as elastic properties and six coefficients describing the Hill yield criterion. Several uniaxial tension and torsion experiments and subsequent data processing were performed to evaluate the properties and coefficients. The typical values obtained for Young’s moduli, shear moduli, and Poisson’s ratio were 121–124 MPa, 37–42 MPa, and 0.25–0.26, respectively. A comparison of the experimental tension and torsion curves with those obtained by a finite element analysis revealed a good correlation with a maximum error of 9.5%. The finite element simulation of a personalised pelvic implant for THR manufactured from the obtained material proved the mechanical capability of the implant to successfully withstand the applied loads.

In the this paper there is a description of the methodology of constructing highly adequate models of materials which are produced additively. The paper consists of introduction to the problem, demonstration of each step of the methodology and conclusions about the method and its applicability. The developed approach is presented on the two additively manufactured metal alloys. The modeling process is based on the orthotropic model of elasto-plastic material behavior. The list of material properties to be found was formulated according to proposed material model. These properties were found from several mechanical experiments. The developed mathematical models of the material studied were checked for compliance to experimental data with use of finite element simulations. Finite element modeling of a complicated 3d-printed lattice structure was performed and compared with the results of natural testing. In order to study the correlation between the material properties and manufacturing process the analysis of microstructure was done.

Current research is devoted to the computer-aided engineering application for direct modeling of the additive manufacturing process and detailed analysis of the resulting shape of the formed part. The utilized approach is based on the idea that it is possible and efficient to perform a numerical simulation of the process of a layer-by-layer building of the analyzed part, considering all the required mechanical and thermal effects. The results of such simulation should allow obtaining the detailed information about the deformed shape of the printed part before running the printing process itself. Such approach allows avoiding the unsuccessful printing attempts, improve the integral stability of the production process and reduce its cost. The paper presents the methodology of preparing a “digital twin” of the additive manufacturing process performed with AlSi10Mg alloy using one of metal machines and running a simulation of the manufacturing process for a representative structural component. The study has shown that implementation of modeling of the manufacturing process before the printing process leads to significant shape improvements of the parts printed, especially in case of performing additional optimization of the support structures. The research outcomes can be well applied for improving the production processes in the companies working with additive manufacturing in order to increase the stability of the processes and accuracy of the printed parts.

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