Végeselemes modellezés az anyagtudományban és az anyagtechnológiákban = Finite Element Modelling in Materials Science and Materials Processing Technologies

Elemző tanulmányt készítettünk technológiai célrendszerekben alkalmazott anyagmodellekről; Számítógépes mérő-adatfeldolgozó rendszert dolgoztunk ki a modellezés szempontjából szükséges anyagjellemzők kísérleti meghatározására; Vizsgálati módszert és számítógépi programot dolgoztunk ki lemezanyagok anizotrópia és keményedési tényezőinek meghatározására és kiértékelésére; Komplex alakíthatósági vizsgálóberendezést építettünk ki alakíthatósági vizsgálatok elvégzésére és számítógépes kiértékelésére; Matematikai modellt dolgoztunk ki ellenállás-ponthegesztés modellezésére; Matematikai modelleket dolgoztunk ki felületötvöző hőkezelések termikus folyamatainak végeselemes modellezésére; A SysWeld végeselemes programrendszerbe integrálható számítómodulokat dolgoztunk ki lézeres felületedzés modellezésére; Elemeztük kerámia anyagok mechanikai viselkedését, matematikai modellt dolgoztunk ki keramikus anyagok törési folyamatainak vizsgálatára Elemeztük a gyorsnitridálás és az ionnitridálás disszociációs és abszorpciós folyamatait a nitridálási folyamat gyorsítása és a termokémiai eljárások gazdaságosságának növelésére; Elemeztük a nitridálás folyamata és a késztermék minősége közötti kapcsolatot, a nitridált réteg összetételének, tulajdonságainak a késztermék tulajdonságára gyakorolt hatását; Háromdimenziós matematikai modellt dolgoztunk ki lézeres felületedzés termikus és metallurgiai folyamatainak elemzésére. Meghatároztuk a lézeres felületedzés optimális paraméter-tartományait. | Material models applied in technological processes were studied; Computer aided measuring and evaluating system for experimental determination of material properties used in FEM systems was elaborated; Method and computer program was developed for the determination of anisotropy and hardening properties of sheet materials; Complex formability testing system was developed for sheet metal formability testing; Mathematical model was elaborated for resistance spot welding; Mathematical model was developed for finite element modeling of thermo-chemical surface treatments; Computing modules were elaborated and integrated into the SysWeld FEM package for modeling laser surface hardening; Mechanical behavior of ceramic materials was studied and mathematical model was elaborated for analyzing the fracture processes of ceramic materials; Dissociation and absorption processes of fast nitriding and ion-nitriding were analyzed to increase the effectiveness and economy of nitriding processes; The relationship between the quality of nitrided products and the nitriding process were analyzed including the effect of the composition and other properties of nitrided layer on the quality of final product; Three-dimensional mathematical model has been developed for the analysis of thermal and metallurgical processes of laser surface hardening; The optimum process parameters of laser surface hardening were determined by FEM modeling

Numerikus modellezés és szimuláció az anyagtudományban és az anyagtechnológiákban = Numerical Modelling and Simulation in material Sciences and Materials Processing Technologies

Végeselemes modellezéssel elemeztük a technológiai folyamatok során lejátszódó anyagszerkezeti, mechanikai és termikus folyamatok együttes hatását. Matematikai modellt dolgoztunk ki egyedi és átlapolódó nyomvonalak alkalmazásával a hőeloszlás végeselemes modellezésére lézeres felületedzés és felületátolvasztás esetére, a hőhatás okozta anyagszerkezeti változások, a keménység- és feszültség-eloszlás meghatározására. Folyamatos hűtésű C-görbék alkalmazásán alapuló számítógépes hőkezelés technológiai tervezőrendszert dolgoztunk ki, acélok edzési, megeresztési, normalizálási és lágyítási technológiáinak elemzésére, műveleti utasítások készítésére, termokémiai eljárások és a betétedzés technológiájának tervezésére. Numerikus modellezési eljárást fejlesztettünk ki sajtolóhegesztési eljárások optimalizálására. Vékonylemezek ponthegesztett kötéseinek optimalizálása témakörben PhD doktori értekezés készült. Számítógépes tanácsadó rendszert dolgoztunk ki különféle hegesztési eljárások technológiai paramétereinek meghatározására, a hegesztés előírt dokumentumainak számítógépes elkészítésére. Lemezalakító eljárások numerikus modellezésével elemeztük a technológiai és szerszámparaméterek hatását. A húzóbordás mélyhúzás numerikus modellezése témakörben PhD doktori értekezés készült. Sorozatszerszámban végezhető lemezalakító eljárások technológiai és szerszámtervezésére alkalmas rendszert dolgoztunk ki általános rendeltetésű CAD rendszerre építve. | The complex structural, mechanical and thermal effects in various technological processes were analysed using FEM. Mathematical model has been elaborated for single and overlapped tracks to determine the temperature distribution, phase transformations, hardness and stress distribution during laser surface hardening and surface melting. Based on the CCT-diagrams, a computer aided technological design program was elaborated for heat-treatment processes, suitable to analyse hardening, case hardening, tempering, normalising and annealing of structural and tool steels, and to design various thermo-chemical heat-treatment processes. Numerical modelling procedure has been elaborated for optimising pressure welding processes. For optimisation of spot-welding processes of thin sheets PhD Thesis was defended. Computer Aided Expert System was elaborated to design various welding processes determining the decisive technological parameters, and preparing the necessary welding specifications (WPS). Applying numerical modelling, the effect of technological and die parameters on various sheet metal forming processes were analysed with particular emphasis on forming of car body panels with deep-drawing. A PhD Thesis was defended on the investigation of deep-drawing processes applying drawbeads. Based on the Unigraphics CAD system, a computer aided technological and die-design system for sheet metal forming processes performed in progressive dies has been elaborated

Comparing the mechanical properties for an al alloy in the cast and wrought condition using the identical solid model

Junior level mechanical engineering students\u27 have designed, rapid prototyped, cast, and tested a link in the laboratory portion of a materials and manufacturing course. A portion of this activity was described originally in a 2005 ASEE Conference paper. The activity has been used for several years in the laboratory portion of the course and it has been very successful. However, one question that comes to mind is May we compare cast mechanical properties with those of wrought properties for similar alloys. During lecture, comparisons of wrought and cast properties are frequently made, and it is shown that ratio of wrought to cast properties is frequently greater than one. To date, the direct comparison has not been done in this course. Using the student designed solid models, it is possible to directly make a rapid prototype part that can be used for the mold in a casting process, and that same model may be used in a CNC machine to make a similar part. Alloy 6061 was used to make the cast links and a section from the five inch diameter ingot will be used to make the CNC produced link. Mechanical properties will be measured using a universal testing machine. The results will be compared, and student interpretation of the results will be evaluated. © American Society for Engineering Education, 2009

Three-dimensional virtual and printed prototypes in complex congenital and pediatric cardiac surgery—a multidisciplinary team-learning experience

10.3390/biom11111703Biomolecules1111170

Antiscaling 3D printed feed spacers via facile nanoparticle coating for membrane distillation

•Surface modification of 3D printed feed spacers was studied for scaling control in MD.•FS nanoparticles coating on spacer favorably altered the latter's surface chemistry.•Increased hydrophobicity and reduced SFE are the main mechanisms of performance.•Scaling reduced by 74% and 60% on the spacer and the membrane, respectively. Surface modification of feed spacers rather than membranes may hold more merit as an antiscaling strategy in membrane distillation (MD), as it avoids compromising the functionality of MD membrane. In this work, an antiscaling polyamide 3D printed spacer was developed for MD. The surface of the printed spacer was coated with fluorinated silica (FS) nanoparticles synthesized via a sol-gel process. The sol-gel approach used to synthesize the FS nanoparticles is considered a convenient and easy approach for engineering the spacer's surface structure and roughness. The performance of the FS coated printed surface was evaluated against other coating materials of different chemical properties. The coated surfaces were characterized using water contact angle measurements, ATR-FTIR, Raman, FESEM-EDX, atomic force and 3D microscopes. The 3D printed surface's microscale roughness and hydrophobicity increased, while its surface-free energy decreased with FS nanoparticles coating. The antiscaling performance of uncoated and FS coated spacers was then assessed in a direct contact MD process, using a scale-inducing aqueous solution of calcium sulfate as its feed. The scalant (Ca2+) attachment on the FS coated spacer was 0.24 mg cm−2, 74% lower than on the uncoated 3D spacer (0.95 mg cm−2). Also, by using the antiscaling FS coated spacer, scaling on the membrane surface dropped by 60%. The predominant factors that helped minimize scaling with FS coating were microscale roughness-induced hydrophobicity and reduced surface-free energy that weakened the scalant 's interaction with the spacer surface. [Display omitted

Stiffness, strength, anisotropy, and buckling of lattices derived from TPMS and Platonic and Archimedean solids

Lattice metamaterials have gained considerable attention due to their distinctive topological structures and multifunctional properties. In this work, the effect of topology, loading conditions, and relative density on the effective mechanical properties of various novel lattice architectures is investigated numerically and experimentally. Thirteen strut-based lattices derived from triply periodic minimal surfaces (five lattices) as well as Platonic (three lattices) and Archimedean (five lattices) solids are considered for the first time, and their anisotropic mechanical properties, including uniaxial, shear, and bulk moduli and strengths as well as their total stiffness, buckling strengths, Poisson’s ratio, and anisotropy are investigated as a function of a wide range of relative densities (0.1% to 37%). Finite element analysis is employed to capture the full effective behavior of these lattices using periodic boundary conditions. Bifurcation analysis is performed to predict the threshold relative density governing their buckling vs yielding deformation behavior. Selected lattice structures of various relative densities are 3D printed using polymer selective laser sintering additive manufacturing technique and tested under quasi-static uniaxial compression where the experimental and numerical results are compared. The numerical results indicate that the deformation behavior can be altered between stretching and bending dominated mode of deformation as function of loading. Archimedean lattices are shown to outperform a wide range of strut-based lattices. This work opens the doors for more investigations of the multifunctional properties of these novel types of lattices and their engineering applications. Furthermore, the generated comprehensive data are useful in optimizing latticed structures using topology optimization techniques.</p