Finite Element Analysis Research Articles

Design of a compact beam transport system for laser-driven proton therapy

Abstract We put forward a new design of a compact beam transport system for intense laser-driven proton therapy, where instead of using conventional pulsed solenoids, our design relies on a helical coil irradiated by a nanosecond laser pulse to generate strong magnetic fields for focusing protons. A pair of dipole magnets and apertures are employed to further filter protons with large divergences and low energies. Our numerical studies combine particle-in-cell simulations for laser-plasma interaction to generate high-energy monoenergetic proton beams, finite element analysis for evaluating the magnetic field distribution inside the coil, and Monte-Carlo simulations for beam transport and energy deposition. Our results show that with this design, a spread-out Bragg peak in a range of several centimeters to a deep-seated tumor with a dose of approximately 16.5 cGy and fluctuation around 2% can be achieved. The instantaneous dose rate reaches up to 109 Gy/s, holding the potential for future FLASH radiotherapy research.

The Impact of Stress Distribution on The Electrical Performance of Different Silver Stretchable Conductive Ink Pattern Using FEA Simulation

Stretchable conductive ink has been widely investigated to be used in the fabrication of stretchable electrical devices. Experimentation methods to test the mechanical and electrical behaviours of the stretchable conductive ink composite are commonly applied; however, not much of the computational approach has been scrutinized to validate the results further. This paper employs the finite element analysis method to investigate the relationship between the stress and strain distribution of the stretchable conductive ink with the highest strain obtained. This research validates the past experimentation works of different patterns of stretchable conductive ink for its stretchability and electrical performance. The maximum Von Mises stress (VMS) and maximum principal strain of the stretchable conductive ink played a significant role in determining its electrical performance, rather than the localisation of high stress and strain at specific locations within the stretchable conductive ink pattern. Zigzag pattern exhibited the lowest maximum stress and strain concentration at 57.826 MPa and 4.05% while straight pattern suffered the highest respective values at 118.143 MPa and 10.39%. The lower maximum Von-Mises stress and principal strain contributed to a better stretchability which is indicated by a higher strain rate prior to electrical conductivity.

Experimental and numerical evaluation of sustainable application of steel slag as an alternative to gravel in compaction piles

The study investigates the application of steel slag as an innovative material for compaction piles in the stabilization of soft soils, offering an eco-friendly alternative to conventional gravel compaction piles (GCPs). Through a comprehensive series of laboratory tests, field experiments, and numerical simulations, this study evaluated the performance, environmental impact, and long-term behavior of steel slag compaction piles (SSCPs). The key findings revealed that steel slag not only provides immediate soil improvement comparable to gravel but also exhibits significant time-dependent increases in strength and stiffness. Standard Penetration Test (SPT) N-ratios (N1/N0, where N1 = N value after improvement and N0 = N value before improvement) were similar for soils reinforced with SSCPs and GCPs after 0 months, but were about 30 % higher in SSCP-reinforced soils after 3 months. This increase was attributed to the cementation of steel slags, suggesting that the compaction pile with increased stiffness due to cementation acts as a compaction pile with an increased area replacement ratio (α). Environmental assessments confirmed that steel slag meets regulatory standards for soil contamination, positioning it as a sustainable option. Settlement analysis after embankment construction showed reduced and more uniform settlements with SSCPs, suggesting superior load distribution capabilities. Finite element analysis compared the behavior of SSCP-reinforced soils at varying α and stiffness of compaction piles, confirming that the cementation of steel slag produces an effect equivalent to increasing α in uncemented piles, thus enhancing the reinforcement effect.

Axial compressive properties of round bamboo-fiber reinforced phosphogypsum composite short columns

Bamboo is an ideal green building material with excellent mechanical properties. Phosphogypsum (PG) is a kind of solid waste residue which is in urgent need of resource utilization and has been used as construction material. In this paper, a kind of round bamboo-fiber reinforced phosphogypsum composite short column was proposed. Axial compression tests of pure bamboo columns, bamboo columns filled with phosphogypsum inside, bamboo columns with phosphogypsum outside and bamboo columns with phosphogypsum inside and outside were carried out to explore the failure mode and mechanical properties of the short columns. The effects of the parameters include bamboo node, hose hoops, size of the bamboo tube and the strength of phosphogypsum on the mechanical properties of the short columns were analyzed, and the theoretical calculation method of the bearing capacity of the short columns was put forward. The results show that the bamboo nodes and hose hoops can improve the bearing capacity, initial stiffness and ductility of the column. The larger the size of the bamboo tube, the better the mechanical properties of the short column. The bearing capacity of round bamboo—phosphogypsum composite short column is higher than that of pure bamboo column. The ductility of bamboo columns with phosphogypsum outside is obviously higher than that of pure bamboo columns. The finite element analysis results are in good agreement with the test results. The theoretical calculation method of the bearing capacity of columns considering the strength reduction coefficient, the bamboo node effect coefficient and the constraint effect in this paper has high accuracy.

Applying 3D-Printed Porous Ti6Al4V Prostheses to Repair Osteomyelitis-Induced Partial Bone Defects of Lower Limbs: Finite Element Analysis and Clinical Outcomes.

The clinical management of partial bone defects in lower limbs, particularly those resulting from osteomyelitis, remains a significant challenge. This study aimed to systematically evaluate the effectiveness of 3D-printed porous Ti6Al4V prostheses in addressing osteomyelitis-induced partial bone defects. We established a comprehensive protocol for utilizing 3D-printed prostheses for bone defect repair, encompassing 3D simulation of prosthesis implantation and internal fixation, finite element analysis (FEA), and clinical implementation. Mimics software facilitated simulation of fixation patterns and screw lengths. FEA modeled bone defects in the distal metaphyseal femur and distal diaphyseal tibia to assess changes in stress conduction pre- and post-prosthesis implantation. The clinical study involved eight patients (average age: 56.3 years) with an average defect length of 14.9 cm. Postoperative outcomes were evaluated using X-rays and the Lower Extremity Functional Scale (LEFS). FEA demonstrated that the implanted prostheses effectively shared stress and reduced the load on residual bone in both models, thus lowering the risk of fractures under external forces. The average follow-up period was 24.5 months, with patients initiating weight-bearing activities on average 7.8 days post-surgery. Serial postoperative X-rays demonstrated long-term stability of the prostheses, with progressive bone regeneration around and integration with the prostheses. While two patients experienced infection recurrence requiring prosthesis removal and debridement, the remaining six showed significant improvement in LEFS scores, increasing from 31.5 preoperatively to 61.0 at the last follow-up. 3D-printed porous Ti6Al4V prostheses effectively restore anatomical integrity and optimize stress conduction in lower limbs, resulting in substantial functional recovery. This innovative approach shows promise for wider clinical adoption and warrants further investigation in medical practice.

Suppression anti-vibration of ultra-small diameter neutron generators for logging while drilling via potting materials

To enhance the reliability of the logging-while-drilling (LWD) neutron generator in harsh environments, this paper proposes a novel polymer monolithic potting protection scheme that can effectively decrease response of the structure under vibrational excitation by selecting suitable polymer potting material and installation method. This paper systematically evaluates the influence of viscoelastic parameters of the polymer potting material on vibration energy dissipation through theoretical calculations. Additionally, it thoroughly investigates the influence of the coupling between the potting modulus and the installation method on the reliability of the structure through finite element analysis. The results demonstrate that potting material with a shorter high-frequency relaxation time can more effectively absorb vibration energy. As the potting modulus increases, the maximum stress of the neutron tube decreases by 96.4%, 93.7%, and 84.7% under short-span, medium-span, and long-span installation methods, respectively. The maximum strain also decreases by 96.6%, 93.9%, and 86.5% respectively. By using the short-span support and high modulus potting material, the local stress and strain can be minimized. A prototype vibration test verifies the effectiveness of this method in improving the reliability of the neutron generator. This analysis provides a reference and reliability prediction for the design of future LWD neutron generators.

Finite element analysis and design of a magnetostrictive material based vibration energy harvester with a magnetic flux path

Abstract This work presents the development of a nonlinear 2D finite element (FE) framework for magnetostrictive material based energy harvesters of beam geometry. The FE model is developed in COMSOL Multiphysics and compared with existing literature for validation. The FE model is subsequently used to study the effect of a closed magnetic flux path, consisting of ferromagnetic components, on the harvester output. Specifically, the voltage output is obtained by performing simulations on unimorph type harvester devices with and without a closed magnetic flux path, both operating at the same natural frequency and volume of the magnetostrictive material Galfenol. The harvester design considered here consists of a magnetostrictive layer (Galfenol) bonded to a steel substrate layer, a tip mass, a pick-up coil and a magnetic flux path consisting of soft iron core and NdFeB permanent magnets. Our results demonstrate a voltage gain of around 70% for the closed flux path design. Furthermore, a proof of concept prototype of the modified flux path design is developed, tested under impulse loading, and the voltage, power output are compared with FE simulation results for validation. The simulation results match well with experimental observations at two operating frequencies for the flux path design.

Four ribbons of double-layer graphene suspending masses for NEMS applications

Graphene ribbons with a suspended proof mass for nanomechanical systems have been rarely studied. Here, we report three types of nanomechanical devices consisting of graphene ribbons (two ribbons, four ribbons-cross and four ribbons-parallel) with suspended Si proof masses and studied their mechanical properties. The resonance frequencies and built-in stresses of three types of devices ranged from tens of kHz to hundreds of kHz, and from 82.61 MPa to 545.73 MPa, respectively, both of which decrease with the increase of the size of proof mass. The devices with four graphene ribbons featured higher resonance frequencies and spring constants, but lower built-in stresses than two ribbon devices under otherwise identical conditions. The Young’s modulus and fracture strain of double-layer graphene were measured to be 0.34 TPa and 1.13% respectively, by using the experimental data and finite element analysis (FEA) simulations. Our studies would lay the foundation for understanding of mechanical properties of graphene ribbons with a suspended proof mass and their potential applications in nanoelectromechanical systems.

Heat Transfer and Entropy Generation on Free Convection Airflow inside a T-shaped Cavity Considering Inner Obstacles

In this study, a numerical analysis of heat and entropy generation on free convection of airflow is performed inside a T-shaped cavity with and without circular obstacles. The T-shaped cavity is formed with two symmetrically isothermal rectangular blocks. A cold temperature is maintained on the cavity's upper wall. The adiabatic walls are connected to heated wall at constant temperature. It is assumed that the flow is laminar, 2-D, and steadily incompressible. The finite element analysis is employed for solving the governing equations. The calculated results are compared and validated with the other published works. The dimensionless velocity (streamlines) and temperature (isotherms) are calculated and illustrated for varying Rayleigh numbers. It is found that the average Nusselt number at the heated walls and entropy generation inside the cavity increase with the increment of Rayleigh numbers. Moreover, the thermal performance effects on natural convection flow are investigated with circular obstacles inside the enclosure. Five cases without and with circular obstacles regarding the boundary conditions are investigated. It is found that the thermal performance of the cavity can be improved by adding two circular obstacles with cool boundary conditions. It is evident that the innovative structure by adding two circular obstacles with cool boundary conditions gives higher average Nusselt number and entropy generation whereas lower Bejan numbers for varying Rayleigh numbers. The study is performed for and . Jagannath University Journal of Science, Volume 11, Number 1, June 2024, pp. 186−202

Utilizing a fully digital approach for oral squamous cell carcinoma treatment and zygomatic implant-based rehabilitation for maxillary defects.

This clinical report details the functional and aesthetic rehabilitation of a patient with a severe maxillary defect secondary to subtotal maxillectomy for oral squamous cell carcinoma (OSCCM) using a maxillary prosthesis anchored by four zygomatic implants. The procedure involved meticulous subtotal maxillectomy and defect repair with zygomatic implant support, incorporating advanced digital surgical methods, including 3D reconstruction, computer-guided surgery, and photogrammetry (Icam4D). A 3D finite element analysis (FEA) was conducted to assess the method's efficacy in analyzing stress distribution around the zygomatic implants. The patient expressed high satisfaction with the prosthesis's functionality, aesthetics, speech, and swallowing capabilities, underscoring the value of zygomatic implant-supported maxillofacial prosthetics. This synergy of advanced planning, surgical precision, and biomechanical analysis marks a significant advancement in maxillofacial prosthetics.

A novel machine learning framework for impact force prediction of foam-filled multi-layer lattice composite structures

Numerical simulations can provide valuable insights for the optimization of design and operational management; however, they are often impractical and computationally intensive. Machine learning methods are appealing to these problems due to their sufficient efficiency and accuracy. In this study, a novel framework for predicting the impact responses of foam-filled multi-layer lattice composite structures (FMLCSs) was proposed by combining the accurate finite element (FE) analyses, surrogate models, fast Fourier transform (FFT) method, and inverse FFT (IFFT) method. Firstly, reliable FM models were established to simulate the crashworthiness of the five FMLCSs under impact loading, including an analysis of energy transformation. Subsequently, surrogate models, namely radial basis function (RBF), polynomial response surface (PRS), Kriging (KRG), and back propagation neural network (BPNN), combined with methods of FFT and IFFT, were employed to predict the impact force-time series of the FMLCSs. More than 1000 frequency points were employed for each type of FMLCS, and all the R-square (R2) values of the established surrogate models exceeded 0.95, indicating that the proposed framework accurately predicted the impact duration and impact responses in the frequency domain. In addition, parameter sensitivity analysis revealed that a high peak impact force was accompanied by a short impact duration. Moreover, increasing the lattice-web height resulted in a significant increase in the impact duration.

Nonlinear Finite Element Simulation and Analysis of Steel Frame Structures Considering Nonlinear Behavior

This paper focuses on investigating the nonlinear behavior of steel frame structures in practical engineering applications. Utilizing finite element analysis, the study simulates the response of structures under extreme loads such as strong earthquakes. By incorporating nonlinear material properties and contact effects, the numerical simulation and analysis explore phenomena such as plastic deformation, yield, and instability in frame structures. The research outcomes contribute to a deeper understanding of the energy dissipation and safety performance of these structures.

Transverse energy absorption performance of sandwich tubes with various origami foldcores

Nowadays, composite sandwich tubes are extensively utilized in the civil and aerospace industries due to their superior strength-to-weight mechanical properties. Origami-based core offers a large enhancement of the mechanical properties, yet little study research focuses on the effect of various foldcore configurations on the transverse mechanical properties of sandwich tubes, necessitating the design method for applications. This study introduces an innovative approach by incorporating origami into the composite sandwich core to enhance the transverse energy absorption capacity. The quasi-static transverse mechanical properties of carbon fibre-reinforced polymer (CFRP) sandwich tubes with foldcores are studied under three-point bending-like local compression and transverse structural compression. A systematic geometric design framework and numerical modelling technique are provided. By integrating finite element analysis and experiments, the research investigates the effects of various origami foldcore configurations and geometric parameters on transverse energy absorption capacity. The experiment setup is provided by sandwich tubular specimens with a full-diamond configuration as the foldcore. The cylindrical tubes (foldcore) of the sandwich structures were manufactured using four plies [0°]4 of T700 (T300) woven CFRP with the hot press moulding (vacuum bag using female and male moulds) technique respectively. Then, the parametric study and damage mode analysis of eight different foldcore patterns (axial Miura, circumferential Miura, diamond, Kresling, and their curved-creased counterparts) were studied. The results showed the superior energy absorption performance of the sandwich tube with Miura-pattern foldcore over the origami-pattern counterparts, nested tube, and traditional honeycomb sandwich tube with CFRP or aluminium-made cores. Therefore, the structural parameters optimisation of the Miura pattern tube was carried out by the Response Surface method (RSM) and a design strategy for increasing the energy absorption capacity was found. The findings offer guidance for designing high-specific energy absorption tubular structures for future advanced engineering applications.

Strain distribution and failure modes of steel lattice tower gusset plates as a function of their geometry

Steel gusset plates (SGP) are structural elements that connect and transfer loads among various members, such as beams, columns, and trusses, in steel structures like buildings, bridges, and lattice towers. Their geometry significantly affects structural performance, requiring a thorough analysis of strain distribution and failure modes to ensure the integrity and safety of structural systems. However, the design and evaluation of lattice tower gusset plates (LTGP) in particular, present challenges due to complex geometries and the lack of universally accepted design methods. This paper presents a comprehensive comparative study of the strain distribution and failure modes of LTGP across different geometries. Experimental tests were conducted using Digital Image Correlation (DIC) on specimens with different configurations, each featuring a single row of bolts. The force–displacement curves and strain distributions were analyzed to determine the influence of gusset plate width, end-distance, and the number of bolts on their behavior. The study compares the experimental data with the prescriptions of design standards. Additionally, it presents numerical modeling of LTGP connections using finite element analysis in ANSYS®, with validation against experimental results confirming model accuracy. The research program is further complemented by a parametric study examining the effects of end-distance, plate width, and bolt spacing on the ultimate strength of LTGP.

Numerical Simulations of a Permeability Test on Non-Cohesive Soil Under an Increasing Water Level

With the intensification of global climate change, extreme rainfall events are occurring more frequently. Continuous rainfall causes the debris flow gully to collect a large amount of rainwater. Under the continuous increase in the water level, the water flow has enough power to carry plenty of loose solids, thus causing debris flow disasters. The intensity of the soil is reduced with the infiltration of rainwater, which is one of the key causes of the disaster. The rise in the water level affects the infiltration behavior. There have been few previous studies on infiltration under variable head. In order to understand the infiltration behavior of soils under the action of water level rises, this paper conducted an indoor permeability test on non-cohesive soil under the condition of an increasing water level. A numerical model was established using the finite element analysis software, Abaqus 6.14, and the pore pressure was increased intermittently to simulate the intermittent increase in the water level. Thereafter, the permeability coefficient and seepage length were changed to interpret the changes in the flow velocity and rate in the permeability test of the non-cohesive soil. The results showed that the finite element numerical simulation method could not reflect the particle movement process in the soil. The test could better reflect the through passage and void plugging phenomenon in soil; when the permeability coefficient alone changed, the velocity of the measuring point with higher velocity changed more violently with the permeability coefficient; when the length of soil seepage diameter was uniformly shortened, the velocity of water flow increased faster and faster.

Bandgap formation mechanism in tacticity inspired elastic mechanical metastructures

Tacticity is long known as a significant contributor in changing the chemical and mechanical properties of the polymers drastically. This study explores mechanism of bandgap formation in elastic mechanical metastructures designed with a focus on tacticity. We introduce metabeams, comprising a primary slender beam embedded with short secondary beams featuring end masses at their tips. The investigation delves into the numerically simulated vibration characteristics of metabeams using finite element analysis, with a subsequent comparison to experimental results for fabricated metabeams. Employing a unit-cell design approach that manipulates spatial and physical parameters, we explore a wide range of uniform and non-uniform metabeam configurations based on the distance between secondary beams and distribution of local resonators as per tacticity. Hence, drawing inspiration from tacticity, we extend our investigation to isotactic and syndiotactic metabeams, altering physical parameters (mass) within the unit cell for both configurations. The strategic distribution of end masses on attached secondary beams introduces unique characteristics to isotactic and syndiotactic metabeams, allowing for the modulation of bandgaps without altering the natural frequencies of the resonators in symmetric and anti-symmetric metabeam designs. Our research demonstrates, incorporating tacticity in metabeam design offers a novel and unconventional approach to modulate the bandgap formation mechanism.

Modeling and Simulation of Material Type Effects on the Mechanical Behavior of Crankshafts in Internal Combustion Engines

This research aims to study the mechanical behavior of the materials most commonly used in crankshaft manufacturing by designing a four-piston crankshaft, analyzing the stresses and displacements resulting from the applied load, and determining vibration frequencies. Additionally, this study examines the thermal behavior of the crankshaft. For this purpose, a three-dimensional model of the crankshaft was designed using CATIA V5 R18 software, and finite element analysis was subsequently performed using ANSYS 2019 R1 software under static, dynamic, and thermal conditions with four different materials in various orientations. To verify the effectiveness of the proposed design, it was compared with a reference design in terms of stresses and displacements. This study also explores improvements in crankshaft geometry and shape. The results indicate that selecting the appropriate material for the working conditions and optimizing the geometry and shape enhance engine performance and reduce the crankshaft’s weight by 20%. The findings were validated by comparing the designs, which support increased productivity and improved durability.

Reduced-Order Modeling for Dynamic System Identification with Lumped and Distributed Parameters via Receptance Coupling Using Frequency-Based Substructuring (FBS)

Paper presents an effective technique for developing reduced-order models to predict the dynamic responses of systems using the receptance coupling and frequency-based substructuring (RCFBS) method. The proposed approach is particularly suited for reconfigurable dynamic systems across various applications, like cars, robots, mechanical machineries, and aerospace structures. The methodology focuses on determining the overall system receptance matrix by coupling the receptance matrices (FRFs) of individual subsystems in a disassembled configuration. Two case studies, one with distributed parameters and the other with lumped parameters, are used to illustrate the application of this approach. The first case involves coupling three substructures with flexible components under fixed–fixed boundary conditions, while the second case examines the coupling of subsystems characterized by multiple masses, springs, and dampers, with various internal and connection degrees of freedom. The accuracy of the proposed method is validated against a numerical finite element analysis (FEA), direct methods, and a modal analysis. The results demonstrate the reliability of RCFBS in predicting dynamic responses for reconfigurable systems, offering an efficient framework for reduced-order modeling by focusing on critical points of interest without the need to account for detailed modeling with numerous degrees of freedom.

Retention and interfacial failure mechanism of single diamond grains in resin-bonded grinding tools

Abrasive grains and the associated bonding agent are the two significant components in the manufacturing of fixed abrasive machining tools. The material properties and interfacial bonding behavior between the grains and the bonding matrix determine machining performance. In precision machining processes with diamond abrasives, the primary failure modes of fixed abrasive tools are grain dislodgement and premature loss, leading to abrupt change in machining load and ultimately causing inaccurate and inefficient machining performance. This study develops a comprehensive model for understanding abrasive grain retention and interfacial failure mechanisms in resin-bonded diamond tools. Finite element analysis of a single diamond grain embedded in a resin matrix was conducted to examine the influence of the grain shape, protruding height, and orientation angle on critical interfacial failure force. A series of single diamond scratching experiments validated the model, revealing that the maximum retention force reached 43.56 N for grains with a 0.9 mm protruding height and a 60° orientation angle. The results also show that, within a specific grain size range, grain shape—quantified by the sphere deviation coefficient proposed in this paper, has the greatest impact on retention and failure behavior. Protruding height plays a secondary role, while the contribution of orientation angle is minimal. These findings provide valuable insights for the design, manufacture, and optimization of precision abrasive machining tools, particularly for applications requiring high precision and reliability.

Performance of Combined Woven Roving and Mat Glass-Fiber Reinforced Polymer Composites Under Absorption Tower Lifting Loads.

This study investigates the structural integrity of a glass-fiber reinforced polymer absorption tower during lifting operations, evaluating factors of safety and stress distribution for both horizontal and vertical scenarios. A key focus is the comparative analysis of surface and volumetric meshing techniques in finite element modeling. Results demonstrate that surface models achieve comparable stress predictions to computationally intensive volumetric models, significantly reducing computational demands without compromising accuracy. For instance, stress at the flange edge with holes was accurately captured using a surface model with 5675 elements (12.79 MPa), yielding similar results to a volumetric model requiring over 94,000 elements (13.37 MPa). Similar computational efficiency and agreement between modeling approaches were observed at the packing support ring-shell joint. Finite element analysis employing Hashin's failure criterion, informed by industry-standard experimental data, revealed safety factors ranging from 1.9 to 2.5 for horizontal lifting and four for vertical lifting. These safety factors indicate sufficient margins for safe operation. While these findings support the feasibility of both lifting methods, further investigation is recommended to address the lower safety factors observed in specific horizontal lifting scenarios. A comprehensive assessment incorporating industry standards, dynamic load effects, and potential mitigation strategies is crucial to ensure the long-term structural integrity of the GFRP absorption tower.