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EN
Rehabilitation of the cranium's bones is considered a complicated procedure that presents a challenge to the surgical staff. Typically, the primary focus when designing an implant should involve selecting optimal design techniques and materials. Material and design should provide a strong, comfortable, simple-to-fit, and attractive implant. Therefore, this study aims to design a suitable customized PEEK implant. Initially, 3D models of the damaged region were created using interactive CAD modelling techniques. While creating the implant model used mirror-based reconstruction. Furthermore, finite element analysis was implemented to evaluate the implant's stability and structural strength. Then morphological analysis was used to assess the precision of virtual fitting. Finally, fused filament fabrication was used to manufacture it. Under simulation, the implant was subjected to a constant load of 50 Newtons and intracranial pressures. According to the simulation results, the maximum Von Mises stress was about 22.057E-2 MPa, the Von Mises strain was 5.8135E-5, and the deformation was 1.9103 µm. That means the maximum recorded stress is quite low in comparison with the material's yield strength. This reflects the ability to endure and maintain safety of the studied implant. While the morphological test showed that the exterior profile curvature contours were uniformly reconstructed, maintaining contiguity between the implant and the skull model, which indicates a suitable fit.
EN
This study investigates the influence of different finite element material modeling approaches on the mechanical response of a femoral bone segment under three-point bending. Four material variants, ranging from homogeneous isotropic to heterogeneous isotropic models, were analyzed to assess their impact on displacement and stress distribution. The results demonstrate that material heterogeneity significantly affects displacement magnitudes, with homogeneous models underestimating deformation compared to heterogeneous ones that better reflect cortical and cancellous bone properties. Stress distribution patterns were primarily governed by geometry and boundary conditions, though stress concentrations near supports were identified as potential numerical artifacts. These findings underscore the importance of incorporating bone heterogeneity and anisotropy in FEM for accurate biomechanical simulations. Future research should focus on advanced anisotropic modeling, nonlinear behavior, and physiologically relevant loading conditions to enhance predictive capabilities, particularly for clinical applications such as implant design and surgical planning.
PL
Niniejsze badanie analizuje wpływ różnych podejść o modelowania materiałowego w metodzie elementów skończonych (MES) na odpowiedź mechaniczną segmentu kości udowej poddanego próbie zginania trójpunktowego. Przeanalizowano cztery warianty materiałowe - od jednorodnych izotropowych po niejednorodne izotropowe - w celu oceny ich wpływu na przemieszczenia oraz rozkład naprężeń. Wyniki wykazały, że niejednorodność materiałowa znacząco wpływa na wielkość przemieszczeń. Modele jednorodne zaniżają wartości deformacji w porównaniu z modelami niejednorodnymi, które bardziej realistycznie odwzorowują właściwości kości korowej i gąbczastej. Rozkład naprężeń był głównie determinowany przez geometrię i warunki brzegowe, choć zidentyfikowano koncentracje naprężeń w pobliżu podpór jako potencjalne artefakty numeryczne. Uzyskane wyniki podkreślają znaczenie uwzględniania niejednorodności i anizotropii tkanki kostnej w MES dla dokładnych symulacji biomechanicznych. Przyszłe badania powinny koncentrować się na zaawansowanym modelowaniu anizotropowym, zachowaniu nieliniowym oraz fizjologicznie uzasadnionych warunkach obciążenia w celu zwiększenia możliwości predykcyjnych, szczególnie w zastosowaniach klinicznych, takich jak projektowanie implantów czy planowanie zabiegów chirurgicznych.
EN
This study investigates the penetration behavior of 5.56 mm underwater projectiles through three target configurations (flat steel, curved steel, and steel-wood composite) using a coupled numerical-experimental approach. Finite element simulations were performed in ANSYS Autodyn employing the Johnson-Cook constitutive model for both the projectile and the targets. Experimental tests were conducted to verify the numerical model under the same conditions. A good agreement (<5% deviation) was obtained between the simulation and experiment in terms of penetration depth and target deformation. The results confirm the reliability of numerical modeling as a practical tool for designing underwater projectile systems and protective structures.
PL
W niniejszej pracy przeanalizowano zjawisko penetracji podwodnych pocisków kalibru 5,56 mm w trzech konfiguracjach celów: stali płaskiej, stali zakrzywionej oraz kompozytu stal-drewno. Badania przeprowadzono z wykorzystaniem podejścia łączącego metody numeryczne i eksperymentalne. Symulacje metodą elementów skończonych wykonano w środowisku ANSYS Autodyn, stosując konstytutywny model materiałowy Johnsona-Cooka zarówno dla pocisku, jak i dla materiałów celu. W celu weryfikacji modelu numerycznego przeprowadzono testy eksperymentalne w identycznych warunkach. Uzyskano dobrą zgodność wyników symulacji z wynikami eksperymentu (odchylenie poniżej 5%) w zakresie głębokości penetracji oraz deformacji celu. Otrzymane rezultaty potwierdzają przydatność i wiarygodność modelowania numerycznego jako praktycznego narzędzia wspomagającego projektowanie podwodnych systemów amunicji oraz konstrukcji ochronnych.
EN
This study employs finite element analysis (FEA) and response surface methodology (RSM) to analyze the stress concentration factor (SCF) in a biaxially loaded isotropic plate with a central countersunk hole. A finite element model is built using ANSY and employed to generate stress concentration factor values. The finite element model was optimized in terms of mesh density and properties based on data from past literature. Five dimensionless parameters are studied: radius to width ratio, thickness to radius ratio, countersink to thickness ratio, σ_y to σ_x ratio and countersink angle. The effect of the different configurations was studied using RSM. Finally, a precise second order equation was produced to estimate the value of SCF with dimensionless parameters.
EN
A systematic approach to the macroscopic damage analysis of bone-like cellular materials is presented in which damage conditions are expressed as tabularized functions of microstructure geometry parameters. Based on three different strain-based microscopic damage criteria, a large number of cellular microstructures, characterized by different values of geometric parameters, are analysed by the finite element method to determine damage factor values for a number of macroscopic strain states. As a result, an exhaustive database is prepared in which macroscopic damage conditions for a variety of microstructures are presented as tabularized parametric functions of both geometric parameters and strain states. A numerical procedure of data interpolation is proposed as a tool to predict parameterized damage surfaces for any bone-like microstructure. The results are made publicly available in an open data repository to enable further research on their characterization and analytical approximation.
EN
The features of the stress-strain state and resistance to fatigue failure of hybrid sucker rods for oil production with a carbon fiber core and a fiberglass shell are considered. The design of the connection of the steel head with the body of the hybrid rod was proposed. It was established that the destruction of the rods under bending load is accompanied by the intensive formation of longitudinal cracks in the form of delaminations in the fiberglass shell and the nucleation of many cracks in it. The finite element method was used to analyze the stress in the connection of the elements of the hybrid rod under bending loads. Based on the distribution of equivalent stresses in the connection of hybrid sucker rods, it is proposed to reduce the concentration of stresses in the transition from the head to the rod by using a plastic insert and ensure the extension of their residual fatigue life.
EN
This study mainly analyzes the stress loading effect of current plastic damaged materials and investigates the stress changes during plastic material damage. The stress structure of the material is analyzed using D-SAP software and the finite element analysis. A new analysis system for plastic damage materials is established. The new system can analyze the damage stress and rigidity magnitude of plastic materials. These studies confirm that new system software can to some extent complete the analysis of stress loading effects on plastic damaged materials. The simulation curve of the software is basically consistent with the experimental values. When compared with traditional software for testing, the new software shows significantly better performance in simulating stress situations and accuracy compared to traditional analysis and simulation software. D-SAP and Digimat software show different deviations during testing. D-SAP has the smallest stress variation, while Digimat strain and stress testing has a larger deviation. In the stiffness test, the deviation between the two software is between 2.04% and 5.3%. In multi-axis pressure testing, D-SAP is consistent with the test values. Therefore, the software used in this study has a better effect on analyzing the stress loading effect of the material, and the deviation between the tested stress and stiffness is smaller. This provides a new direction for stress analysis of materials.
PL
Modelowanie procesów spawania stało się w ostatnim czasie jednym z głównym narzędzi wspomagających badania eksperymentalne oraz wdrożenia produkcyjne procesów spawania. Literatura jest bardzo bogata w publikacje zawierające elementy modelowania jedno-źródłowych procesów spawania, jednak rosnące zainteresowanie przemysłu stosowaniem spawalniczych źródeł hybrydowych stwarza nowe pole do badań tych procesów z zastosowaniem symulacji numerycznych. W niniejszej pracy podjęto próbę stworzenia konwencjonalnego i hybrydowego źródła ciepła w oprogramowaniu dedykowanym do wykonywania symulacji numerycznych metodą MES – LUSAS FEA 14.7. W wyniku przeprowadzonych badań udało się zweryfikować klasyczny model Goldaka na podstawie badań pola temperatury oraz cyklu cieplnego spawania. Ponadto, badania wykazały, że zaproponowany model hybrydowego źródła ciepła, w dość dobrym stopniu odzwierciedla zmiany rozkładu temperatury przy spawaniu hybrydowym.
EN
The modelling of welding processes has recently become one of the most important tools to support the experimental research and the production implementation of welding processes. The literature is very rich in publications containing elements of single source modelling of welding processes, but the growing industrial interest in the use of hybrid welding sources creates a new field for the study of these processes using numerical simulations. In the present study, an attempt has been made to create a conventional and hybrid heat source in a software dedicated to performing numerical simulations using the FEA method - LUSAS FEA 14.7. As a result of the study, based on studies of the temperature field and thermal cycle of welding, it was possible to verify the classical Goldak model. Furthermore, the study showed that the proposed hybrid heat source model fairly well reflects the temperature distribution changes in hybrid welding.
EN
This paper presents two solutions employing locally resonant metamaterial to level the mass-air-mass resonance impact on the sound insulation. The first operates on the cantilever beam resonance, and the second uses masses vibrating in flexural mode cut out from the additional panel. Both structures are mounted between two lightweight, honeycomb cardboard panels with a double-wall resonance of 420 Hz. Solutions were analysed numerically for their vibration and acoustic properties and measured in the reverberation chamber, resulting in information about the dispersion curve, effective dynamic mass, and sound insulation. The analytical results of Sound Transmission Loss (STL) and the experimental measurements of diffused-field Sound Reduction Index (SRI) proved the existence of sound-insulation enhancement. The local rise in SRI resulted in an increase of broadband Weighted SRI up to 5 dB.
EN
This investigation proposes the utilization of diverse dielectric materials to reduce electric field emissions in shielded capacitive coupler for wireless power transfer. To identify the most influential dielectric materials in minimizing electric field emissions, Finite Element Analysis (FEA) was conducted. The dielectric materials incorporated in this proposed initiative encompass rubber, glass, FR4, halowax, air, mineral oil, and paper. These dielectrics served as separators between the coupler and the shielding plate. The work demonstrates the electric field emissions at various values in distinct locations of the exposure area, encompassing the top, bottom, and side of the coupler. The result shows the air is the most suitable insulator among all dielectric materials.
PL
W tym badaniu zaproponowano wykorzystanie różnorodnych materiałów dielektrycznych w celu zmniejszenia emisji pola elektrycznego w ekranowanym sprzęgaczu pojemnościowym do bezprzewodowego przesyłania mocy. Aby zidentyfikować materiały dielektryczne, które najbardziej wpływają na minimalizację emisji pola elektrycznego, przeprowadzono analizę elementów skończonych (FEA). Materiały dielektryczne uwzględnione w proponowanej inicjatywie obejmują gumę, szkło, FR4, halowax, powietrze, olej mineralny i papier. Dielektryki te służyły jako separatory pomiędzy łącznikiem a płytą ekranującą. W pracy przedstawiono emisję pola elektrycznego o różnej wartości w różnych miejscach obszaru narażenia, obejmującego górę, dół i bok łącznika. Wynik pokazuje, że powietrze jest najbardziej odpowiednim izolatorem spośród wszystkich materiałów dielektrycznych.
PL
Artykuł dotyczy analizy możliwości podniesienia dopuszczalnej prędkości na moście kolejowym w Tczewie. Opisano strukturę mostu, przeprowadzone modele obliczeniowe, badania dynamiczne pod ruchem oraz analizy numeryczne po kalibracji.
EN
The article presents a comprehensive analysis aimed at assessing the feasibility of increasing the permissible speed on a bridge in Tczew. This analysis included a numerical Finite Element Analysis (FEA) which covered static, modal, and dynamic analyses for four types of truss spans. The natural frequencies of the structure, maximum deflections, and extreme accelerations for speeds ranging from 60 to 120 km/h were investigated. The study involved in situ non-destructive testing (NDT). The NDT methods were instrumental in calibrating the models and provided actual values for natural frequencies, displacements, and accelerations. The final step involved the precise measurements of the track geometry using a UPS-80 trolley, which revealed irregularities over the supports where levelling devices were located. The integration of both theoretical and NDT data enabled a comparison with the established safety and structural integrity standards, which led to maintaining the existing speed limit of 60 km/h on the railway bridge in Tczew.
EN
Spur gear, helical gear, worm gear, and bevel gear are all important components in industrial applications such as vehicles, pushes, conveyors, elevators, bowl mill, rolling mills, ribbon blender, machine tools, aeroplanes, and windmills. When various types of defects, such as wear, tooth breakage, corrosion, and scratches on bearings, appear in gearboxes, normal machine function may be abruptly terminated. As a result, output and dependability suffer. As a result, several quality tracking and evaluation approaches have been adopted by companies. Finite element analysis (FEA) is one of the approaches. This research paper presents the FEA of a ribbon blender worm gear pair by using Ansys 18.0 to identify the weak gear of the worm gear pair, natural frequency, and deformation. Proe-5 utilized for creation of three-dimensional geometry of threaded worm and toothed worm wheels, as well as other related elements such as shafts and bearings. Steel is used for the worm, shaft, and bearing, whereas bronze is used for the worm wheel. Ansys 18.0 is implemented to carry out worm gear pair model analysis. The results demonstrate that the worm wheel had the most deformation when compared to the worm, and that the natural frequency is greater than the operational frequency of the worm gear pair. The findings of the research study, worm wheel deteriorate early than worm, model analysis plays a significant role in vibration monitoring of worm gear pair, and this work is valuable for further fault analysis of ribbon blender worm gearbox utilising vibration response.
EN
Additive manufacturing (AM) technologies have been gaining popularity in recent years due to patent releases – and in effect – better accessibility of the technology. One of the most popular AM technologies is fused deposition modeling (FDM), which is used to manufacture products out of thermoplastic polymers in a layer-by-layer manner. Due to the specificity of the method, parts manufactured in this manner tend to have non-isotropic properties. One of the factors influencing the part’s mechanical behavior and quality is the thermoplastic material’s bonding mechanism correlated with the processing temperature, as well as thermal shrinkage during processing. In this research, the authors verified the suitability of finite element method (FEM) analysis for determining PET-G thermal evolution during the process, by creating a layer transient heat transfer model, and comparing the obtained modelling results with ones registered during a real-time process recorded with a FLIR T1020 thermal imaging camera. Our model is a valuable resource for providing thermal conditions in existing numerical models that connect heat transfer, mesostructure and AM product strength, especially when experimental data is lacking. The FE model presented reached a maximum sample-specific error of 11.3%, while the arithmetic mean percentage error for all samples and layer heights is equal to 4.3%, which the authors consider satisfactory. Model-to-experiment error is partially caused by glass transition of the material, which can be observed on the experimental cooling rate curve after processing the temperature signal.
EN
“Y-shaped” airway stents have been widely used in the treatment of airway diseases, especially airway stenosis, due to their excellent flexibility. However, the current research on the flexibility of “Y-shaped” airway stents is still blank, limiting the possibility of improving the performance of stents in complex clinical disease. This study aimed to establish multi-dimensional evaluation of the flexibility of a novel segmented “Y-shaped” airway stent and two kinds of conventional stents. We evaluated the flexibility of the segmented stent, wholly knitted stent, and silicone stent by in vitro mechanical testing and finite element analysis methods. That is, the bending force and spring-back force of three kinds of stent were measured in left-right, anterior-posterior and longitudinal directions. The torque of the stents in torsion-recovery test of branches of stent was also executed. Finite element analysis was performed to evaluate the change of diameter. According to the detection, the bending force and spring-back force of the branch of the segmented stent during left-right and anterior-posterior compression, and the torque during torsion and recovery were lower than those of the other two stents. In finite element analysis, the diameter change of the segmented stent was minimal among the three stents. The flexibility of the segmented “Y-shaped” airway stent was better than that of the conventional “Y-shaped” airway stents, indicating that it has better adaptability and resistance to compression when implanted in the body.
EN
The mechanical overloading of temporomandibular joint (TMJ) is generally linked to temporomandibular disorders (TMD). However, in patients with a typical combination of maxillofacial morphology and occlusal features, the reduction of joint load and treatment with general occlusal splints are often ineffective. This study investigates the biomechanical behavior of the stomatognathic system in a TMD patient with personalized splints by finite element analysis. The therapeutic position, determined based on the intercuspal position, served as the basis for designing personalized customized splints. The design of occlusal contact and splint structure was evaluated in terms of their impact on the maximum stress level in the TMJ and the biting forces on the dentition. The relationship between joint stress and biting force was further examined during treatment with different customized splints. In preoperative case, there was a significant increase in stress level and stress concentration in the medial to posterior band of the articular disc. However, in all customized splint cases, the highest stress area shifted to the intermediate zone and exhibited a decrease. Notably, the bi-splints demonstrated superior ability in relieving overloading and balancing the occlusal force on both sides of the dentition, as verified by clinical treatment. The predictable simulated results offer valuable interactive information regarding TMJ overload, aiding doctors in making better-informed clinical decisions in future.
EN
The prefabricated concrete frame structure system has advantages such as short construction period and good seismic performance, but its deformation and energy dissipation capacity are poor under earthquake action, making it prone to damage. By improving the analysis and simulation functions of existing finite element analysis for prefabricated structures, the engineering applicability of the analysis algorithm has been improved. Then, a finite element model has been established for collaborative optimization, and a parameterized optimization scheme that meets the seismic reduction requirements has been obtained. The results show that the optimization method proposed in the study has a better effect in seeking the minimum cost, and meets the design requirements of the specification. The optimization scheme of prefabricated concrete frames designed by the research institute based on finite element analysis can efficiently optimize various parameters, greatly improving the structure energy dissipation and seismic performance.
EN
Steel-concrete composite beam has been increasingly applied to large span cable-stayed bridges. It takes full advantage of the material properties of steel and concrete. However, the concrete deck bears tension in the negative moment zone, such as zero block, which is disadvantageous to structures. Aiming at this problem, a finite element model of the zero block in the negative moment zone of a semi-floating cable-stayed bridge is built, and the local mechanical performance of the bridge deck under completed status is studied. Based on the analysis results, three improvement measures have been proposed. The improvement effect of each method and composed of three methods has been studied. The numerical results show that the whole zero block zone is in the compressed state under the combined action of the bending moment and axial force of the stay cable. However, the local negative moment effect in the zero block zone is very prominent under the support of the diaphragm plate. Removing parts of the diaphragm plate at the bearing position can significantly improve local mechanical behavior in the concrete deck, which transfers the local support to the adjacent two diaphragm plates. The composed improvement effect is prominent when the three measures are adopted simultaneously.
EN
In this work, a new, simple method is presented, which enables identification of material properties of solids basing on the digital image correlation (DIC) measurements. It may be considered as a simplified alternative of low computational complexity for the well-known finite element model updating (FEMU) method and virtual fields method (VFM). The idea of the introduced sub-global equilibrium (SGE) method is to utilize the fundamental concept and definition of internal forces and its equilibrium with appropriate set of external forces. This makes the method universal for the use in the description of a great variety of continua. The objective function is the measure of imbalance, namely the sum of squares of residua of equilibrium equations of external forces and internal forces determined for finite-sized part of the sample. It is then minimized with the use of the Nelder–Mead downhill simplex algorithm. The efficiency of the proposed SGE method is shown for two types of materials: 310 S austenitic steel and carbon-fiber-reinforced polymer (CFRP). The proposed method was also verified based on FE analysis showing error estimation.
EN
Shape memory alloys (SMAs) are metallic materials that are characterized by their ability to restore their original shape after large deformation when activated by heating. This unique property renders SMAs appealing for various civil engineering applications. Iron-based SMAs (Fe-SMAs), including alloys like Fe–Mn–Si, stand out due to their cost-effectiveness and high strength. The primary focus of this research lies in the computational modeling of Fe-SMA strips utilized to reinforce damaged concrete structures. To achieve this, details from an experimental test are leveraged for the computational simulation of real-scale reinforced concrete beams that were first loaded to some level of damage, then released and strengthened, and subsequently retested. The strengthening approach involves the application of external Fe-SMA strips wrapping around the beams. This paper presents an original computational modeling setup that incorporates a switch option for the Fe-SMA material. This feature enables one to use a single simulation platform for the whole process. The significance of this method originates from its capacity to ensure a robust analysis that includes all simulation steps-testing unstrengthened beams, installing and heating Fe-SMA strips, and testing both damaged and strengthened beams-in a single, multi-step analysis. The computational simulation results were compared with the outcomes of the experimental test, revealing an acceptable level of agreement. The findings indicate a substantial increase in both shear strength and ductility as a result of the application of Fe-SMA strips. Additionally, parametric and mesh sensitivity studies were conducted. These aimed to investigate the mesh dependency of the model and to identify the optimal mesh size. Furthermore, variations in the details of the Fe-SMA strips, including thickness, width, quantity, and effect of applied temperature were explored to compare the outcomes of different applications of these strips.
EN
Accelerated bridge construction (ABC) is prevalent all over the world attributable to its technical advantages including the higher construction efficiency, less traffic disruption, and higher construction quality. Grouting sleeves (GS) and grouting corrugated pipes (GCP) are the traditional connection methods of ABC in high seismic regions, with the disadvantages of uncompacted grouting and high requirement of construction accuracy. To this end, this paper developed a new type of prefabricated concrete bridge pier connected with ultra-high performance concrete (PCBP–UHPC) jacketing to solve the problems. To validate the seismic performance of the proposed innovative bridge pier, quasi-static tests on three full-scale specimens PCBP–UHPC, PCBP–GS, and PCBP–GCP were carried out. The results indicated that the failure mode of specimen PCBP–UHPC was similar to that of specimens PCBP–GS and PCBP–GCP with the characteristics of longitudinal steel yielding and concrete crushing at the base of the hollow pier. The obvious plastic hinge outward shifting could be observed during the loading for specimen PCBP–UHPC. The positive ultimate load of specimen PCBP–UHPC was 636.33 kN, which was 14.8% and 13.3% higher than those of specimens PCBP–GS and PCBP–GCP, respectively. In addition, a refined finite element model (FEM) was established by ABAQUS to provide an in-depth understanding on the failure mechanism of the proposed PCBP–UHPC. The parametric analyses were conducted to reveal the influence of the socket depth and axial compression ratio on seismic performance of the proposed PCBP–UHPC. The results indicated that the socket depth had little effect on seismic performance of the prefabricated pier, while the ultimate load bearing capacity of specimen PCBP–UHPC increased to some extent as the increase of the axial compression ratio. The present research work provides an innovative prefabricated bridge pier and a comprehensive experimental–numerical understanding on its seismic performance, which is beneficial for its engineering application.
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