FEA Model Research Articles

Deformation analysis on dispersive clamping for CFRP circular cell honeycombs based on finite element simulations

Dispersive clamping can meet the precise positioning requirement for CFRP circular cell honeycombs due to its discontinuity, but faces complex clamping deformation due to its weak rigidity and heterogeneous properties. Clamping deformation analysis plays a crucial role in guiding fixture optimization and improving machining accuracy. In this paper, an equivalent alternative to adhesive bonding between cells is developed to simulate the mechanical behavior of the resin connecting the cells. The simulation results demonstrate that the proposed method effectively predicts the response of honeycombs under shear load. Further, a FEA model for clamping is developed, which accounts for the cohesive contact between cells. The results show that dispersive internal clamping has a great effect on shear deformation and load transfer paths of honeycombs. By optimizing relevant parameters, the shear deformation of the clamped cells can be restricted and the RMS of the deformation in the Z-direction can be reduced by up to 13.62%.

Nonlinear dynamic responses of bistable cantilever shell subjected to in-plane foundation excitation

This paper focuses on the nonlinear vibration and snap-through behavior of bistable cantilever shell under in-plane foundation excitation. A combination of experimental and finite element analysis methods are used for an in-depth exploration. The experimental setup is built to accurately simulate the in-plane foundation excitation environment and measure the nonlinear responses of bistable cantilever shell. By adjusting excitation parameters, the dynamic behavior of the structure under different conditions is systematically observed, especially the snap-through process from one stable-state to the other. A corresponding finite element model is established based on ABAQUS software to verify the accuracy of the experimental results and further understand the motion mechanism, which takes into account factors such as material nonlinearity and geometric large deformation. By comparing the experimental results with the simulation data, a high degree of consistency is exhibited. This not only verifies the reliability of the experimental method but also demonstrates the accuracy and applicability of the established FEA model. The nonlinear vibration and snap-through behavior of bistable cantilever shell are quite sensitive to the excitation levers.

Deep Rolling Process Modeling Using Finite Element Analysis in Residual Stress Measurement on Rail Head UIC860 Surface

This study investigates the effects of deep rolling parameters, pressure, speed, and offset, on the residual stress distribution and material deformation in UIC 860 Grade 900A railway rails. We will model deep rolling to simulate the process and predict the residual stress profile in railway rails. Subsequently, we will rigorously compare and analyze the FEM simulation results with experimental data to optimize deep rolling parameters for improved residual stress distribution. Using both experimental methods and finite element analysis via ANSYS 2023 R1, the study varied deep rolling parameters. Experimental deep rolling pressure was set at 150 bar, speed at 1800 mm/min, and offset at 0.1 mm, while FEA simulations predicted corresponding pressures of 157 bar and speed of 1796.52 mm/min. These parameter settings were chosen to induce significant surface compressive stresses that could enhance the material’s mechanical performance. The experimental results showed an average compressive residual stress of 498.9 MPa, closely aligning with the FEA-predicted value of 502.5 MPa. A paired t-test revealed no statistically significant difference between the two results, with a T-value of −0.22 and a p-value of 0.833, validating the reliability of the FEA model. The consistent deformation observed in both experimental and FEA simulations, especially with a 0.1 mm offset, confirmed that the rolling parameters were effective in producing uniform stress distribution, albeit with a slightly extended processing time due to the small offset. Overall, the findings confirm that optimizing the deep rolling parameters of pressure, speed, and offset leads to favorable residual stress distributions and improved material properties. The results indicate that FEA is a reliable tool for predicting the outcomes of deep rolling, and this study provides a strong foundation for further refinement of the process to enhance performance in practical applications, such as railway rail treatments.

A Novel Cooling System for High-Speed Axial-Flux Machines Using Soft Magnetic Composites

Demand is high for small, lightweight, and power-dense machines. However, as power increases and size decreases, rejecting losses becomes more difficult. Many novel cooling systems have been developed, which have allowed machines to be made smaller while increasing power. This paper proposes a cooling system making use of soft magnetic composite (SMC) cores to improve cooling specifically in a high-speed axial-flux machine via the use of an integrated cooling channel in the SMC core. A series of experiments on a prototype machine are performed and the experimental data are used to determine a set of parameters for the FEA thermal model. Using the thermal FEA model, a comparison is completed with a traditional closed cooling system using laminated steels and an attached cooling plate.The SMC machine is then simulated at speeds up to 160 krpm and currents up to 8 A. To achieve the same coil temperature between the two designs, the laminated steel model required 4 MPa contact pressure at 10 krpm and 5 MPa contact pressure at 20 krpm. At the same time, the novel design removed approximately 20% more heat per shear air gap surface area and approximately 15% more heat per total machine surface area than the version with the attached cooling plate. Extending the operating range of the model to 160 krpm demonstrated that the maximum temperature rise remained below 180 °C.

Rolling over Simulation and Structure Optimization of Electric Automobile Charging Gun

Abstract The anti-rolling performance of the electric vehicle charging gun is critical in its daily work. Firstly, to improve the accuracy of the simulation, the tire FEA model is modeled in detail, including the tire airbag simulation tire pressure, the Beam unit simulation tire bead wire, etc. We also calibrate the FEA model of the charging gun. Secondly, through the rolling-over simulation and comparison with the test results, both the gun heads are broken and the damage positions of both are the same, which indicates the accuracy of the rolling-over simulation model. Finally, based on the results of the rolling-over simulation and test, the structure of the charging gun is optimized, the rolling-over simulation and test are carried out again, and the charging gun head and the gun shell are not damaged. The results show that the simulation model can guide the design of the anti-rolling performance of charging gun.

High-Velocity Impact Performance of Ballistic Fabric Using Core-Spun Compound Yarns.

In this paper, the usage of core-spun compound yarns in ballistic fabric to improve ballistic performance is considered, as with the use of core-spun compound yarns, the yarn friction inside the fabric is enhanced, and, therefore, the energy absorption capability of the fabric is expected to increase. Three types of fabric were developed and compared. Fa refers to a woven type made with 100% Kevlar® filament yarns. Fb was woven with core-spun compound aramid yarns, which were made of Kevlar® filament yarns spun with staple aramid fiber. Fc was woven with core-spun compound polyester yarns, which were made of Kevlar® filament yarns spun with staple polyester fiber. There were two main purposes for comparing these types. The first was to confirm if the ballistic performance could be improved with the usage of core-spun compound yarns instead of pure filament yarns. The second was to investigate if different compositions of spun fiber would influence ballistic performance. The research results are positive and quite interesting. They show that the usage of core-spun compound yarn could indeed help to increase ballistic performance and that core-spun compound aramid yarns are better than core-spun compound polyester yarns in this function. The research was carried out using both ballistic tests and FEA models.

Research on size effects in fracture properties and residual life prediction for high-speed train axles

As critical load-bearing components of high-speed trains, the design and evaluation of axles primarily adhere to the principle of infinite life, supplemented by systematic flaw detection to ensure their operational safety. The establishment of detection intervals heavily depends on damage tolerance analysis informed by fracture mechanics. The size effect has a great influence on the fracture mechanical properties of materials, and how to accurately assess the remaining life considering the dimensional effects has been an open question in terms of safety in the railroad industry. Consequently, this research focuses on full-scale axle crack propagation tests, exploring the fracture mechanics properties critical to the life analysis of full-scale axle cracks under very high cycle fatigue (VHCF) condition. The findings demonstrate that size effects profoundly affect the fatigue fracture properties of high-speed train axles, especially regarding fatigue crack growth thresholds. Importantly, within the stable growth region, variations in fatigue crack growth rates across different scales prove to be minimal. Subsequently, a finite element model of the full-scale axle was established using the fatigue crack growth rate curve derived from experimental data. The validity of this FEA model was confirmed through bench test results, and predictions of the residual life for axles with cracks were formulated. This comprehensive analysis provides the foundation for developing an ultrasonic detection interval schedule for axles.

Simulation and mechanical testing of 3D printing shin guard composite materials

ABSTRACT This study critically examines the composite material's mechanical properties and performance for 3D-printed shin guards. It contains a thermoplastic polymer matrix with short carbon fibre reinforcement. Shin guard stress and deformation under impact loading were modelled using FEA models. The composite material was 3D-printed and tested for tensile, flexural, and impact properties. The entire cycle of FEA models and careful mechanical testing allows for the development and evaluation of new composite materials and designs. The finite element analysis, such as maximum von Mises stress, is 2890.5 MPa. The carbon fibre-reinforced composite's mechanical properties, including tensile strength, flexural strength, and impact resistance, showed a considerable improvement over those of the unreinforced polymer. The solid design could be heavier and less adaptable than the pattern. Compared to unreinforced polymers, carbon fibre improves strength, stiffness, and impact resistance for the 3D-printed composite. This result thus proves that 3D-printed carbon fibre-reinforced composites could make superior sports protective equipment like shin guards. The FEA calculations and extensive mechanical testing provide a dependable framework for creating and testing these new composite materials and systems.

Influence of printing orientation on power-law hardening and ductile damage parameters for 3D-printed SS316L steel: experimental and FEA approach

In the present investigation, the selective laser melting (SLM) technique has been utilized for the 3-dimensional printing (tensile test specimens) of SS316L steel powder at 00 (horizontal) and 900 (vertical) angles. Further, an experimental and finite element analysis approach has been made to analyse the effect of printed orientation or direction on the Hollomon power law parameters (strain hardening exponent (n) and strength coefficient (K)) and ductile damage parameters (fracture strain (εf), stress triaxiality (η) and strain rate ( ε ̇ )). The influence of printing orientation on plastic deformation behavior has also been analysed. The results revealed that 00 angle 3D-printed specimens exhibited 11.05%, 21.97% and 9.50% more yield strength, tensile strength and elongation than 900 angle 3D-printed tensile test specimens. Further, the strain hardening exponent (n) and strength coefficient (K) (Hollomon power law hardening model parameters) for 00 angle 3D-printed specimens are 35.80% and 32.47% more than the 900 angle 3D-printed tensile test specimens respectively. The fracture strain for 00 angle 3D-printed specimens is 37.82% less than the 900 angle 3D-printed tensile test specimens. The percentage difference between FEA and experimental results is less than 5% which shows the good prediction capability of estimated Hollomon power law parameters and ductile damage model parameters with developed FEA model for 00 and 900 3D printed specimens.

Fatigue life predictions for welded boiler water walls

Boiler water walls experience in-phase thermo-mechanical loading during start-ups and shut-downs, leading to low cycle fatigue (LCF) failure. This study aims at establishing an FEA-based failure prediction method for estimating the fatigue performance and service life of the welded water walls. The developed model is validated for predicting failure in the defect-free uniaxial fatigue specimens. Stress-mechanical strain hysteresis loops and accumulated inelastic strain energy density per cycle parameters are extracted from fatigue tests at 0.4%, 0.6%, and 0.7% strains. A combination of cyclic plasticity and continuous damage mechanics (CDM) theory is utilized to predict fatigue crack initiation sites and estimate the specimen fatigue life. Accumulated damage has been calculated for the life cycle of each specimen. FEA model predicted failure and service life agrees well with the experimental results. The established failure analysis parameters are then transferred from the specimen level to the water wall component level, thereby estimating the service life of defect-free water walls at 750 cycles.

Finite element analysis evaluation of hypothetical alternative treatment scenarios for neglected developmental dysplasia of the hip.

The study aimed to evaluate three different degrees of correction in the surgical treatment of neglected developmental dysplasia of the hip (DDH) using finite element models based on computed tomography. Three tridimensional FEA models of hypothetical post-operative (PO) outcomes were developed, based on three tridimensional CT of a pediatric patient diagnosed with luxated neglected DDH: One with the acetabular index of the contralateral hip (CLAT); another based on a theoretical Bombelli biomechanical model (BMB); and another recreating the patient's actual PO. The stresses in the affected hip were greater than those in the unaffected hip. CLAT showed the greatest stress and the smallest loading zone (LZ). In contrast, BMB showed the smallest stress and the biggest LZs. The approach based on the BMB gave the best results in terms of the distribution of the stresses over the hip, whereas the worst was CLAT. Qualitatively, estimating the stability and range of movement of the hip, the PO case was considered the best.

Effect of Prosthetic Material and Support Type on Stress Distribution of Fixed Partial Dentures: A Finite Element Study

Choosing an appropriate prosthetic material for the superstructure of an implant-supported or tooth-implant supported fixed partial denture (FPD) is crucial for the success of the prostheses. The objective of this study was to examine the effect of prosthetic material type and tooth-to-implant support on stress distribution of FPDs using three-dimensional finite element analysis (3D FEA). Two FEA models were generated, distinguished by their support configurations: Model I representing an FPD supported by implants, and Model II depicting an FPD supported by both a tooth and an implant. Two different restorative materials, porcelain-fused-to-metal (PFM) and monolithic zirconia, were evaluated for stress distribution under axial and oblique loads of 300 N applied to the pontic. Under both axial and oblique loading conditions, the maximum von Mises stress values were observed to be higher in the implant-abutment complex of both zirconia implant-supported and tooth-implant-supported FPDs compared to PFM FPDs. In the case of axial loading, comparable stress values were found in the cortical bone for PFM (12.65 MPa) and zirconia implant-supported FPDs (12.71 MPa). The zirconia tooth-implant-supported FPD exhibited the highest stress values in the implant-abutment system.

Semi-automated finite element analyses of surgically treated acetabular fractures to investigate the biomechanical behaviour of patient-specific compared to conventional implants

BackgroundIn acetabular fracture surgery, understanding the biomechanical behaviour of fractures and implants is beneficial for clinical decision-making about implant selection and postoperative (early) weightbearing protocols. This study outlines a novel approach for creating finite element models (FEA) from actual clinical cases. Our objectives were to (1) create a detailed semi-automatic three-dimensional FEA of a patient with a transverse posterior wall acetabular fracture and (2) biomechanically compare patient-specific implants with manually bent off-the-shelf implants.MethodsA computational study was performed in which we developed three finite element models. The models were derived from clinical imaging data of a 20-year-old male with a transverse posterior wall acetabular fracture treated with a patient-specific implant. This implant was designed to fit the patient's anatomy and fracture configuration, allowing for optimal placement and predetermined screw trajectories. The three FEA models included an intact hemipelvis for baseline comparison, one with a fracture fixated with a patient-specific implant, and another with a conventional implant. Two loading conditions were investigated: standing up and peak walking forces. Von Mises stress and displacement patterns in bone, implants and screws were analysed to assess the biomechanical behaviour of fracture fixation with either a patient-specific versus a conventional implant.ResultsThe finite element models demonstrated that for a transverse posterior wall type fracture, a patient-specific implant resulted in lower peak stresses in the bone (30 MPa and 56 MPa) in standing-up and peak walking scenario, respectively, compared to the conventional implant model (46 MPa and 90 MPa). The results suggested that patient-specific implant could safely withstand standing-up and walking after surgery, with maximum von Mises stresses in the implant of 156 MPa and 371 MPa, respectively. The results from the conventional implant indicate a likelihood of implant failure, with von Mises stresses in the implant (499 MPa and 1000 MPa) exceeding the yield stress of stainless steel.ConclusionThis study presents a workflow for conducting finite element analysis of real clinical cases in acetabular fracture surgery. This concept of personalized biomechanical fracture and implant assessment can eventually be applied in clinical settings to guide implant selection, compare conventional implants with innovative patient-specific ones, optimizing implant designs (including shape, size, materials, screw positions), and determine whether immediate full weight-bearing can be safely permitted.

Evaluating the Feasibility of Short Dental Implants as Alternatives to Long Dental Implants in Mandibular Bone: A Finite Element Study.

This study uses finite element analysis to investigate the potential application of shorter dental implants as a substitute for longer implants in the lower jaw (mandible). FEA allows the evaluation of the stress patterns around the implant-bone interface, a critical factor for successful osseointegration. Ten models were generated, encompassing five long (L1-L5) and five short implant models (S1-S5) with variations in diameter and length. Hypermesh software was utilized to meticulously prepare the FEA models, ensuring accurate mesh generation. The FEA simulations were conducted under four distinct loading scenarios (100 N occlusal load, 40 N lateral load, 100 N oblique at 30°, and 100 N oblique at 45°) to realistically mimic the forces exerted during biting, using an ABAQUS CAE solver. The results revealed that the von Mises stress generated within the short implant models was demonstrably lower compared to their long implants. Additionally, a significant drop in stress was observed with increasing the diameter of the short implants, to a certain diameter range. These findings suggest the potential for successful substitution of long implant model L4 with short implant model S4 due to the demonstrably lower stress values achieved. Furthermore, the data indicates the possibility of utilizing short implant models S3 and S5 as alternatives to long implant models L3 and L5, respectively. These observations hold significant promise for evaluating the feasibility of replacing long implants with shorter variants, potentially leading to a reduction in implant-related failures.

The Effects of using PEEK Coping and Different Restorative Materials on the Stress Distribution in Tooth and Implant- supported Prostheses under Static Loading: 3D FEA.

This study was designed to evaluate the influence of utilizing Polyetheretherketone (PEEK) coping and three different dental restorative materials in the success of tooth and implant-supported fixed partial dentures (TISFPD) in the maxillary posterior region, under static loading by 3-Dimensional Finite Element Analysis (3D FEA). Six 3D FEA models were designed assuming the extraction of maxillary first and second molars. Bone, implant, abutment, PEEK coping, second premolar, periodontal ligament (PDL) and six 3-unit TISFPD with different restorative materials [Porcelain-Fused-to-Metal (PFM), PEEK-Composite (PC), Monolithic Zirconia (MZ)] were modeled. Then, PEEK copings were modeled to be cemented onto the implants as a double-crown system for the first three groups (PFMPEEK, PCPEEK and MZPEEK) whereas, the next three groups (PFM, PC, MZ) excluded a PEEK coping in their designs. The prostheses were loaded twice, vertically and obliquely. From the determined points, 250 N for vertical loading (0o to the long axis) and 200 N for the oblique loading (30o to the long axis) were applied. Von Mises tension, maximum and minimum principal tension value criterias were analyzed. Regardless of the material used for suprastructure, the maximum average stress was reduced by using PEEK coping. Considering the maximum stress distribution, PC appeared to have the highest stresses on the cortical bone, implant and screw. Additionally, the von Mises stresses formed in the PDL for each model were lower when PEEK coping was included in the design of the TISFPD, reducing the risk of intrusion. The stress distribution was positively affected by the PEEK coping in TISFPD design, reducing bone resorption and failure. This elastic material used generated lower stresses in the bone and implant, while no significant effect was found on stresses around natural teeth.

Investigation of high-performance alkali-activated slag concrete-filled steel tubular members under lateral impact

This paper studied the behaviour of High-performance Alkali-activated slag Concrete-Filled Steel Tubular members under transverse impact along with axial compression. Combining alkali-activated slag concrete with concrete-filled steel tubes provides a novel composite material incorporating the benefits of alkali-activated slag concrete and steel tubes. Alkali-activated slag concrete, known for its environmentally beneficial traits compared to traditional concrete, improves sustainability, while concrete-filled steel tube increases structural stability. Seven specimens composed of one hollow tube and six high-performance alkali-activated slag concrete-filled steel tubular specimens were tested using a drop hammer test setup to enhance our understanding of the structural performance of high-performance alkali-activated slag concrete-filled steel tubular members. A finite element analysis model was then established to broadly compare the impact resistance of circular high-performance alkali-activated slag concrete-filled steel tubular members. The mid-span displacement and impact test durations of specimens subjected to lateral impact and axial compression were assessed using a high-speed video camera called Phantom V411. This analysis includes the examination of maximum impact load, impact plateau value, maximum displacement, residual displacement, indentation, impact duration and strain responses, and an investigation into the failure modes of the specimens. The obtained results closely align with the experimental outcomes, indicating the effectiveness of the FEA model in predicting the behaviour of circular high-performance alkali-activated slag concrete-filled steel tubular members.

Burst pressure prediction of cord-rubber composite structures using global–local nonlinear finite element analysis

This study aims to develop a model to predict the burst pressure of a dry filament wound cord-rubber composite pressure vessel under hydrostatic internal pressurization using a submodelling based global–local FEA model. The model links the global displacements of a rebar-based model to obtain the local deformation state in a single rhomboidal representative volume. Emphasis is placed on capturing the local stress concentrations in the fibers due to the unique filament winding mosaic pattern. Fiber damage is included in the local model using a maximum principle strain criteria. Verification of the created model is done experimentally on industrially manufactured burst-test specimens. Measurements for displacement during the experiments are taken photographically, while the burst pressure is captured using a pressure transducer. The final error between the burst pressure of the samples and the experimental demonstrators is approximately 6.5%, a marked improvement over conventional models with truss and rebar elements as fibers.

Phased Array Ultrasonic Imaging for Characterizing Steel with an Elevated Temperature Gradient.

In this research work a phased array ultrasonic Testing (PAUT) is used for inspecting steel at elevated temperature. Velocity of ultrasound is affected by temperature of medium, and the study of ultrasound is done when it is propagating through High temperature media of steel. For this purpose, a steel sample is heated from one surface and temperature gradient is generated in it. The methods like Full Matrix Capture (FMC) and Total Focusing Method (TFM) are used to generate real time ultrasonic image at particular instant of time. It is a method to generate the real time two-dimensional ultrasonic image. The FEA model of steel with temperature gradient is created and the ultrasonic inspection methods, FMC and TFM are applied in order to generate the image by taking elementary A-scan data from simulation and plotting the same to generate the image. The simulation results can be validated using high temperature experiments with steel samples and the experimental data can be taken to use TFM algorithm for ultrasonic evaluation. These TFM images provide a visual representation of the steel cross section at elevated temperature at specific instances, facilitating early-stage in-situ monitoring and optimization of the steel solidification process.

Effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition: A finite element analysis.

Studies have not been done to evaluate the peri-implant stress exerted by materials(like PEEK and resin matrix ceramics) in different osseointegration conditions. To investigate the effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition using finite element analysis. Eighteen different 3D FEA models of implant fixed with abutment were created involving 6 different occlusal materials (Heat cured temporary acrylic resin (PMMA), Bis-GMA, PEEK, Lithium disilicate, Resin matrix ceramics and translucent Zirconia) and different osseointegrated conditions (50%, 75%, 100%). Models were subjected to loading vertically and obliquely followed by evaluation of stress distribution. The results of the simulation obtained were analysed in terms of Von mises, maximum principal and minimal principal stresses using descriptive stastistics. PMMA (40.14 MPa on vertical loading and 66 MPa on oblique loading) resulted in the highest stresses and lithium disilicate (24 MPa on vertical loading and 52.40 MPa on oblique loading) resulted in least stresses among all the crown materials. Upon oblique loading, von Mises stress increases except for translucent zirconia and lithium disilicate (52.444 MPa on 50%, 47.733 MPa on 75%, and 43.973 MPa on 100% osseointegration). Minimal principal stress values decreased with increase in osseointegration upon oblique loading for PMMA, BisGMA, and PEEK. Translucent zirconia and lithium disilicate offer a better stress transmission. Minimal principal stress values of PEEK and BisGMA decreased with increasing osseointegration.

Expanding manufacturability of sheet-based triply periodic minimal surfaces by electron beam powder bed fusion in Wafer theme

Porous biomaterials based on triply periodic minimal surfaces (TPMS) are intensely studied and discussed in the literature. Manufacturing of these structures with a complex geometry became possible using additive manufacturing methods, having their own specifics and challenges. Previously, we demonstrated that sheet-based gyroids, one of TPMS structures, manufactured by electron beam powder bed fusion in Melt and Wafer themes could possess identical mechanical properties (quasi-elastic gradient). In the current research sheet-based gyroids were produced using Wafer Theme with five different settings, including electron beam current and scan speed variation with MultiBeam turned on and off, in attempt to obtain thin walls without losing mechanical performance. Mechanical tests revealed that the specimens manufactured with higher beam line energy on average show better mechanical properties. The specimens produced with MultiBeam showed slightly lower mechanical properties, and do not demonstrate significant improvement in the TPMS surface roughness. According to SEM studies, the average wall thickness was about 0.4 mm for specimens with high line energy, and 0.3 mm for low line energy. Through-hole defects on the horizontal surfaces, noticed and discussed by us previously, have larger average area of the hole and more irregular shape for increased beam line energy. TPMS surface morphology of the specimens produced with higher beam energy and no MultiBeam was on average more even. According to EBSD, α/α` martensite with laths oriented in a Widmanstätten basket-weave pattern was observed with no β phase in the resulting material. No significant differences in microstructure between specimens produced with different beam energy was detected. FEA modeling revealed the impact of the wall thickness, through holes size and orientation on quasi-elastic gradient of a gyroid. It was demonstrated that, through holes with small size located on the horizontal surfaces (layer plane) have only a minor impact on the mechanical properties of the samples if they are not extremely abundant.