Material models for simulation of dynamic forming operations

Bakalářská práce obsahuje základní informace o modelech materiálů pro simulace dynamických dějů ve tváření. Popisuje simulační software založený na metodě konečných prvků a jeho využití při simulaci dynamických dějů ve tváření. Uvádí základní teorii o mechanických vlastnostech materiálu a způsoby jejich zjišťování při dynamických podmínkách zatěžování. Srovnává jednotlivé konstitutivní rovnice, které vystihují chování materiálu v závislosti na teplotě a rychlosti deformace.The work deals with basic information about material models for simulation of dynamic forming processes. It describes software based on the finite element method and its use for simulation of dynamical forming processes. Next it presents basic theories about mechanical behaviour of materials under dynamical loading conditions and thein evaluation. It compares constitutive equations which describe materiál behaviour depended ontemperature and strain rate.

Vibrations at machining of metals

Práce ve své teoretické části uvádí matematický popis kmitání, způsoby vzniku chvění při obrábění a měření modálních parametrů obráběcího stroje. Praktická část obsahuje sestavení lobe diagramu stability pro poloautomatický soustruh SPN 12 CNC, určený na základě naměřených vlastních frekvencí stroje s konkrétním nástrojem a materiálem pomocí zařízení Brüel Kjaer.The diploma work deals with a mathematical description of vibration and its generation when machining. Moreover, some techniques of modal parameters measurement in the theoretical part are included. The practical part is designed and based on the measured natural frequencies of the machine with specific tool and materials. In conclusion, a lobe diagram stability for semiautomatic lathe SPN 12 CNC and selected machining operation is specified by means of apparatus.

Legal liability of a psychotherapy provider in non-medical facilities and the related death of a psychotherapist from a legal point of view

Tématem příspěvku je analýza vybraných právních aspektů právní odpovědnosti poskytovatele psychoterapie mimo zdravotnická zařízení a právní konsekvence smrti takovéhoto psychoterapeuta v kontextu ochrany dat klientů.The topic of the paper is an analysis of selected legal aspects of the legal liability of psychotherapy providers outside health care facilities and the legal consequences of the death of such a psychotherapist in the context of client data protection

Zacházení s informacemi při poskytování psychoterapie v mimozdravotnických zařízeních a problematika poskytování informací třetím stranám

Tématem příspěvku jsou vybrané právní aspekty poskytování psychoterapie mimo zdravotnická zařízení, konkrétně problematika zacházení s daty klientů a poskytování informací třetím stranám

Application of Carbon–Flax Hybrid Composite in High Performance Electric Personal Watercraft

Within the herein presented research, we studied the applicability of flax fabrics for composite parts in personal watercrafts in order to enhance damping of vibrations from the engine and noise reduction (which is relatively high for contemporary carbon constructions). Since the composite parts are intended to be exposed to humid environments requiring high levels of mechanical properties, a carbon–flax composite was selected. Samples of carbon, fiberglass, flax, and hybrid carbon–flax twill and biax fabrics were subjected to tensile and three-point bending tests. The mechanical properties were also tested after exposure of the samples to a humid environment. Damping was assessed by vibration and noise measurements directly on the complete float for samples as well as real parts. The hybrid carbon–flax material exhibited lower values of tensile strength than the carbon material (760 MPa compared to 463 MPa), but, at the same time, significantly higher than the other tested materials, or flax itself (115 MPa for a twill fabric). A similar trend in the results was observed for the three-point bending tests. Vibration tests and noise measurements showed reductions in vibration amplitude and frequency when using the carbon–flax hybrid material; the frequency response function for the watercraft part assembled from the hybrid material was 50% lower than for that made of carbon. Testing of samples located in a humid environment showed the necessity of surface treatment to prevent moisture absorption (mechanical properties were reduced at minimum by 28%). The tests confirmed that the hybrid material is satisfactory in terms of strength and its contribution to noise and vibration damping

A Non-Destructive Impedance Method Using Resonance to Evaluate the Concentration of Steel Fibers in Concrete

Steel-fiber reinforced concrete is a composite material characterized by outstanding tensile properties and resistance to cracking. The concrete, however, exhibits such characteristics only on the condition that the steel fibers in the final, hardened composite are distributed evenly. Current methods to evaluate the distribution and concentration in a fiber composite are either destructive or exhibit a limited capability of evaluating the concentration and orientation of the fibers. In this context, the paper discusses auxiliary techniques and laboratory tests that evaluate the density and orientation of the fibers in a composite material, presenting an innovative approach to impedance-based non-destructive testing. The actual methodology utilizes the resonance of the measuring device and the measured sample set; the desired state occurs within the interval of f = 10 kHz and 2 GHz

Time-discrete integration of finite deformations

Some necessary implications for the time discrete integration of finite deformations will be discussed together with particular Runge--Kutta--Munthe-Kaas schemes, when the geometrical structure of the space of Cauchy-Green deformation tensors, implicitly contained in the principle of virtual power, is taken into account