Flexible structures (FS) are thin shells with a pattern of holes. The stiffness of the structure in the normal direction is reduced by the shape of gaps rather than by the choice of the material based on mechanical properties such as Young’s modulus. This paper presents virtual prototyping of 3D printed flexible structures with selected planar patterns using laboratory testing and computer modeling. The objective of this work is to develop a non-linear computational model evaluating the structure’s stiffness and its experimental verification; in addition, we aimed to identify the best of the proposed patterns with respect to its stiffness: load-bearing capacity ratio. Following validation, the validated computational model is used for a parametric study of selected patterns. Nylon—Polyamide 12—was chosen for the purposes of this study as an appropriate flexible material suitable for 3D printing. At the end of the work, a computational model of the selected structure with modeling of load-bearing capacity is presented. The obtained results can be used in the design of external biomedical applications such as orthoses, prostheses, cranial remoulding helmets padding, or a new type of adaptive cushions. This paper is an extension of the conference paper: “Modeling and Testing of 3D Printed Flexible Structures with Three-pointed Star Pattern Used in Biomedical Applications” by authors Repa et al.

The purpose of this prospective study was to determine whether the cost and cost-effectiveness of early rehabilitation after stroke are associated with the degree of initial disability. The data for cost calculations were collected by the bottom-up (micro-costing) method alongside the standard inpatient care. The total sample included 87 patients who were transferred from acute care to early rehabilitation unit of three participating stroke centers at the median time poststroke of 11 days (range 4–69 days). The study was pragmatic so that all hospitals followed their standard therapeutic procedures. For each patient, the staff recorded each procedure and the associated time over the hospital stay. The cost and cost-effectiveness were compared between four disability categories. The average cost of the entire hospitalization was CZK 114 489 (EUR 4348) with the daily average of CZK 5103 (EUR 194). The cost was 2.4 times higher for the immobile category (CZK/EU: 167 530/6363) than the self-sufficient category (CZK/EUR: 68 825/2614), and the main driver of the increase was the cost of nursing. The motor status had a much greater influence than cognitive status. We conclude that the cost and cost-effectiveness of early rehabilitation after stroke are positively associated with the degree of the motor but not cognitive disability. To justify the cost of rehabilitation and monitor its effectiveness, it is recommended to systematically record the elements of care provided and perform functional assessments on admission and discharge.

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BEHAVIOUR OF FRICTIONAL JOINTS IN STEEL ARCH YIELDING SUPPORTS ZACHOWANIE POŁĄCZEŃ CIERNYCH W PODATNYCH ŁUKOWYCH OBUDOWACH STALOWYCHThe loading capacity and ability of steel arch supports to accept deformations from the surrounding rock mass is influenced significantly by the function of the connections and in particular, the tightening of the bolts. This contribution deals with computer modelling of the yielding bolt connections for different torques to determine the load-bearing capacity of the connections. Another parameter that affects the loading capacity significantly is the value of the friction coefficient of the contacts between the elements of the joints. The authors investigated both the behaviour and conditions of the individual parts for three values of tightening moment and the relation between the value of screw tightening and load-bearing capacity of the connections for different friction coefficients. ANSYS software and the finite element method were used for the computer modelling. The solution is nonlinear because of the bi-linear material properties of steel and the large deformations. The geometry of the computer model was created from designs of all four parts of the structure. The calculation also defines the weakest part of the joint's structure based on stress analysis. The load was divided into two loading steps: the pre-tensioning of connecting bolts and the deformation loading corresponding to 50-mm slip of one support. The full Newton-Raphson method was chosen for the solution. The calculations were carried out on a computer at the Supercomputing Centre VSB-Technical University of Ostrava.

The total load-bearing capacity of steel arch yielding roadways supports is among their most important characteristics. These values can be obtained in two ways: experimental measurements in a specialized laboratory or computer modelling by FEM. Experimental measurements are significantly more expensive and more time-consuming. However, for proper tuning, a computer model is very valuable and can provide the necessary verification by experiment. In the cooperating workplaces of GIG Katowice, VSB-Technical University of Ostrava and the Institute of Geonics ASCR this verification was successful. The present article discusses the conditions and results of this verification for static problems. The output is a tuned computer model, which may be used for other calculations to obtain the load-bearing capacity of other types of steel arch supports. Changes in other parameters such as the material properties of steel, size torques, friction coefficient values etc. can be determined relatively quickly by changing the properties of the investigated steel arch supports.