Mechanical Finite Element Analysis Research Articles

Frictional Slip and Incremental Dynamic Analysis of Plate-rubber Bearing Continuous Girder Bridge by Ambient Temperature in Cold Region

Special mechanical environment, the environmental temperature or stress transformation easily to the final mechanical properties of the bridge components performance changes. The impact of the cold zone environment on the plate rubber-bearing beams is the object of study, Jining Road refined mechanics finite element analysis of the structural dynamic response study under seismic action. The results show that low temperature leads to bearing friction slip and material parameter changes, which affects the self-oscillation frequency and seismic susceptibility of the bridge. Due to the temperature-induced changes in the material properties and mechanical properties of the bearings, the first principal period of the bridge increases by 3% at high temperature for the EH and decreases by 19% at low temperature for the EL when compared to the first principal period under normal temperature conditions. Under different extreme temperature conditions, the fundamental period of the bridge is longitudinal, and the effective mode vibration participation mass is more than 90%. The maximum crossover frequency VALmax reaches 75.6 dB. Compared with room temperature, the bearing stress increased by 27.6% to 45.5%. The effect of EL stress change should be considered in the design of bridges in the alpine region.

Continuous CF/PA6 Composite Aircraft Window Frame Manufactured via a Novel Winding Compression Process.

Using fiber-reinforced polymer composite to replace metal in window frames has become a trend in aircraft manufacturing to achieve structural weight reduction. This study proposes an innovative winding compression molding process for continuous production of aircraft window frames using continuous carbon fiber-reinforced polyamide 6 thermoplastic composite filaments (CF/PA6). Through process parameter optimization, the production cycle of CF/PA6 composite window frames was controlled within 5 min, with an ultra-low porosity of 0.69%, meeting aviation application standards. Combining mechanical property experimental tests and finite element analysis, the mechanical performance of window frames made from three different materials was compared and evaluated. In the hoop direction, the mechanical performance of the continuous CF/PA6 thermoplastic window frames were significantly higher than that of chopped CF/epoxy compression molding window frames and aluminum alloy window frames. In the radial direction, the maximum strain occurred at the corner with the highest curvature of the frame due to the absence of fiber reinforcement, resulting in weak pure interlayer shear. Nevertheless, the thermoplastic CF/PA6 winding compression molded window frame still exhibited a high resistance to crack propagation and damage, as evidenced by the absence of any detectable sound of microdamage during testing with a 9000 N load. It is believed that achieving a further-balanced design of hoop-radial performance by appropriately introducing radial ply reinforcement can lead to a significant weight reduction goal in the window frame. The findings in this study provide an innovative process reference that can be universally applicable to high-speed and near-net-shape manufacturing without material waste of continuous fiber-reinforced thermoplastic composite products.

Assessment of fiber reinforcement strategies for additively manufactured thermoplastic composites using mechanical testing and finite element analysis

Assessment of fiber reinforcement strategies for additively manufactured thermoplastic composites using mechanical testing and finite element analysis

Lithium Metal under Static and Dynamic Mechanical Loading

Macro-scale mechanical testing and finite element analysis of lithium metal in compression have been shown to suggest methods and parameters for producing thin lithium anodes. Consideration of engineering and geometrically corrected stress experiments shows that the increasing contact area dominates the stress increase observed during the compression, not strain hardening, of lithium. Under static loading, the lithium metal stress relaxes, which means there is a speed of deformation (engineering strainrate limit of 6.4×10−5 s−1) where there is no increase in stress during compression. Constant displacement tests show that stress relaxation depends on the initial applied stress and the amount of athermal plastic work within the material. The finite element analysis shows that barrelling during compression and the requirement for high applied stresses to compress lithium with a small height-to-width ratio are friction and geometric effects, respectively. The outcomes of this work are discussed in relation to the diminishing returns of stack pressure, the difficulty in closing voids, and potential methods for designing and producing sub-micron lithium anodes.

A new method used in the process of cleaning channels from turbidity and sediments

Article mentions the use of a new technology for cleaning irrigation systems from muddy sediments. This technology was modeled and tested using Ansys Mechanical Finite Element Analysis (FEA) Software for Structural Engineering. Analytical analyzes were carried out to maintain the design parameters of irrigation system coatings. As a result of the analysis, a deformable tooth device using a wedge with a unit of k (N/m) is applied to the coating with an impact force F (N) at an angle of α =100-300, so that it is compressed in the range of Δl =5-15 (mm) without damaging the coating of the irrigation system. determined.

Finite element mechanical analysis of ipsilateral approach and contralateral approach in unilateral bilateral endoscopic spine surgery

BackgroundUnilateral bilateral endoscopic spine surgery (UBE) is often performed to treat lumbar spinal stenosis and disc herniation. It has become a prominent method in endoscopic spine surgery because of its very low learning curve and broader operative field of vision. Currently, the ipsilateral approach and contralateral approach have been established for disc herniation in the foraminal area, intervertebral foramen region, or pedicle region. The contralateral method offers many benefits over the ipsilateral approach, including less bone labour during microsurgical decompression and the preservation of facet joints. However, because it uses the interlaminar window approach, it inevitably involves osteotomy of the patient’s superior and inferior articular processes, which may result in corresponding deterioration in the spine’s biomechanical stability and subsequent adjacent facet joint diseases caused by facet joint degeneration postoperatively.ObjectiveAs a result, the purpose of this work is to use a finite element model to evaluate how the ipsilateral approach and contralateral approach in unilateral bilateral endoscopic spine surgery affect spinal stability while treating identical intervertebral disc herniation.Study designIn this study, a three-dimensional lumbar-sacral spine model was built and verified. Osteotomies were conducted for armpit-type lumbar disc herniation (LDH), periradicular-type LDH, and shoulder-type LDH. Postoperative lumbar spine models of the ipsilateral approach and contralateral approach in unilateral bilateral endoscopic spine surgery were developed. The von Mises stress on the endplate, shear force on the annulus fibrosus, pressure inside the intervertebral disc, and range of motion (ROM) of the L3 segment were all determined. The results of our well-validated model showed that osteotomy done in the ipsilateral approach deteriorated most biomechanical metrics.ResultsIn the majority of loading conditions, the contralateral approach caused the intervertebral disc’s biomechanical properties to increase, and the ipsilateral approach caused the intervertebral disc’s biomechanical properties to increase sharply more than the contralateral approach.ConclusionThe contralateral approach, which is now extensively employed in unilateral bilateral endoscopic spine surgery, may be regarded as an ideal surgical alternative for treating lumbar disc herniation without producing iatrogenic instability. This approach has a low facet joint reduction rate, minimum soft tissue injury, and precisely identifies the midline of the central spinal canal during the retraction of the thecal sac and nerve roots.

Load capacity and fracture modes of instrumented tooth roots under axial compression.

To investigate the influences of root canal instrumentation on the load capacity and fracture modes of tooth roots under axial compression by performing mechanical tests and finite element analysis (FEA). Thirty bovine incisor roots were trimmed into cylinders of 5.0mm diameter. They were randomly divided into two groups, one with root canals instrumented to ∼2.0mm in diameter, and one without instrumentation. The specimens were fractured under uniaxial compression at a crosshead speed of 0.2mm/min, and then micro-CT was used to reveal the fracture patterns in three dimensions. FEA was further performed, using the extended finite element method (XFEM), to compare the compression-induced stress distributions and the initiation and propagation of root fractures in both groups. The mean fracture load of the non-instrumented group (2334±436N) was statistically significantly higher than that of the instrumented group (1857±377N) (p<0.01). Three types of root fractures were identified according to the path and length of the cracks: end-face crack, partial-length crack, and full-length crack. As to the fracture modes, the incidence of partial-length root fracture was the highest in both groups (60% for the non-instrumented group and 53.3% for the instrumented group), followed by that of full-length fracture (26.7% and 40%, respectively) and then end-face fracture (13.3% and 6.7%, respectively). The percentage of full-length fracture was slightly higher in the instrumented group. FEA showed that the compression induced higher Tresca stresses but lower maximum principal stresses in the canal walls of the instrumented group. The XFEM simulations predicted that the fracture of both groups initiated from the outer root surface near an end face and propagated axially to the middle third of the root and radially towards the root canal. These numerical results agreed well with our experimental findings. Within the limitation of this study, it was found that root canal instrumentation could significantly decrease the load capacity of tooth roots and potentially increase their susceptibility to full-length root fracture under uniaxial compression.

Hybrid Aluminized Fiberglass Reinforced Composite Pipes: A Framework for Safety Use in Industries

Introduction: Polymer matrix composites have been utilized in various industries due to their low cost and good strength-to-weight ratios. AIM: This study aims to investigate the effectiveness of filament-wound fiber-reinforced polymer composite pipes. The focus is on aluminized fabric tubes, which are flexible and heat-resistant tubes made from a glass fabric and laminated with a layer of aluminum. AIM: This study aims to investigate the effectiveness of filament-wound fiber-reinforced polymer composite pipes. The focus is on aluminized fabric tubes, which are flexible and heat-resistant tubes made from a glass fabric and laminated with a layer of aluminum. Method: These tubes offer unique properties that make them suitable for various applications, especially in environments with high temperatures or exposure to radiant heat. Fiber Reinforced Plastic (FRP) pipes are highlighted for their lightweight, easy transportation, low maintenance, corrosion resistance, design flexibility, and anti-freezing performance. The study delves into the use of aluminized glass fiber for high-temperature applications, with a specific focus on enhancing high-temperature withstanding properties. Result: In addition, the present research also conducts tests to study the structural strength of normal glass fabric tubes and aluminized glass fabric tubes. The fabrication of composite pipes is achieved through a filament winding process with a zero-degree winding angle using a manually operated filament winding machine. Mechanical testing and Finite Element Analysis (FEA) simulations using ANSYS® are also performed to compare glass fiber-reinforced plastic pipes with hybrid aluminized fiber-reinforced plastic pipes. Conclusion: The application of aluminized glass fiber in both the internal and external layers of the pipes improves the pipe’s strength and ability to endure high temperatures.

Predictive modelling of the cross‐sectional reduction of smoke extraction ducts under fire resistance test

AbstractIn‐service performance of single compartment smoke extraction ducts is evaluated in the fire resistance test with the method described in EN 1366‐9. Failure due to cross‐sectional reduction is caused by the deflections of the steel walls which are exposed to a differential pressure and a high temperature airflow coming from the furnace.This study presents a methodology for the prediction of the deformation of smoke extraction duct steel walls using 1‐way transient coupling between computational fluid dynamics (CFD) airflow simulation and mechanical finite element analysis (FEA). The resulting deformation is compared with a full‐scale experimental test. The degradation of the steel mechanical behavior with temperature is calibrated using experimental data. This coupled analysis provides insights into the tools and methodology developed for the digitalization of fire resistance testing.

3D-Printed PEEK/Silicon Nitride Scaffolds with a Triply Periodic Minimal Surface Structure for Spinal Fusion Implants.

The issue of spine-related disorders is a global healthcare concern that requires effective solutions to restore normal spine functioning. Spinal fusion implants have become a standard approach for this purpose, making it crucial to develop biomaterials and structures that possess high osteogenic capacities and exhibit mechanical properties and dynamic responses similar to those of the host bone. This study focused on the fabrication of 3D-printed polyether ether ketone/silicon nitride (PEEK/SiN) scaffolds with a triply periodic minimal surface (TPMS) structure, which offers several advantages, such as a large surface area and uniform stress distribution under load. The mechanical properties and dynamic response of PEEK/SiN scaffolds with varying porosities were evaluated through mechanical testing and finite element analysis. The scaffold with 30% porosity exhibited a compressive strength (34.56 ± 1.91 MPa) and elastic modulus (734 ± 64 MPa) similar to those of trabecular bone. In addition, the scaffold demonstrated favorable damping properties. The biological data revealed that incorporating silicon nitride into the PEEK scaffold stimulated osteogenic differentiation. In light of these findings, it can be inferred that PEEK/SiN TPMS scaffolds exhibit significant potential for use in bone tissue engineering and represent a promising option as candidates for spinal fusion implants.

The Optimization of Welding Spots’ Arrangement in A-Pillar Patchwork Blank Hot Stamping

With increasingly severe environmental problems, energy saving and environmental protection have become two important issues to be solved in the automobile industry. Patchwork blank hot-stamping technology can be used to obtain light-weight and high-strength parts and is thus increasingly used in the manufacture of autobody parts. Because the main blank and the patched blank need to be connected through spot welding before forming, the welding spots’ arrangement has a great influence on the formability of the part. In this study, a thermal–mechanical coupling finite element analysis model of A-pillar patchwork blanks was established. With the thickness of the patched blank, the distance between the welding spot and the external contour of the patched blank, and the number of welding spots as optimization variables, together with the maximum thinning rate and the maximum welding spot force as objectives, the influence of welding spot arrangement on forming quality was analyzed, and the welding spots’ arrangement was optimized using a central composite design (CCD), the response surface method (RSM), and the genetic algorithm (GA). The results showed that when the initial welding spot was located close to the contour of the patched blank, the bending moment was greater when the weld spot passed through the die corner, leading to the rupture of the welding spot or its surrounding base material due to the greater thinning rate. When the patched blank was thicker than the main blank, the main blank cracked during the forming process due to a greater increase in the thinning rate. The optimal solution of the weld spot arrangement on the A-pillar patchwork blanks was a 1.2 mm thick main blank, 0.8 mm thick patched blank, a distance of 29 mm between the weld spot and the contour line of the patched blank, and 16 weld spots. Hot-stamping experiments were conducted using the optimized weld spots’ arrangement, and high-quality parts were obtained.

Biomechanical Investigation of Bone Screw Head Design for Extracting Stripped Screw Heads: Integration of Mechanical Tests and Finite Element Analyses.

Enhancing the design of bone screw head sockets to prevent stripping and improve the torque required for smooth unscrewing is a significant challenge in orthopedic applications. This research aims to establish a quantitative methodology by integrating mechanical testing with finite element (FE) simulations to determine a safe limitation depth for the screwdriver when engaging with the hexagonal socket, thus avoiding stripped screw heads. A FE model was developed to investigate the biomechanical responses of the screw head design. Five custom-made hexagonal sockets were manufactured, and single load torsional tests were conducted to assess the mechanical performance of the screws and drivers. The results from the mechanical tests were compared with the FE simulations, demonstrating a close agreement and confirming the model's validity. Furthermore, additional FE models were created to study the impact of manufacturing tolerances on the socket width and screwdriver width. The findings revealed that the maximum torque to failure for the four designs was lower than the margins specified in ISO 6475. Additionally, increasing the depth of the screwdriver led to higher maximum torque values. This research suggests that the technique of screw insertion, specifically the depth of the driver tool within the screw socket, holds greater importance in preventing stripped screw heads than the design and manufacturing width of the bone screw's hexagonal socket and screwdriver. This confirms the importance of screwdriver engagement inside the bone screw socket to prevent stripped screw heads and sheds light on the added value of maximum torque prediction for future design modifications.

Establishment of finite element model of varus-type ankle arthritis and biomechanical analysis of different correction models for tibial anterior surface angle

To establish the finite element model of varus-type ankle arthritis and to implement the finite element mechanical analysis of different correction models for tibial anterior surface angle (TAS) in supramalleolar osteotomy. A female patient with left varus-type ankle arthritis (Takakura stage Ⅱ, TAS 78°) was taken as the study object. Based on the CT data, the three-dimensional model of varus-type ankle arthritis (TAS 78°) and different TAS correction models [normal (TAS 89°), 5° valgus (TAS 94°), and 10° valgus (TAS 99°)] were created by software Mimics 21.0, Geomagic Wrap 2021, Solidworks 2017, and Workbench 17.0. The 290 N vertical downward force was applied to the upper surface of the tibia and 60 N vertical downward force to the upper surface of the fibula. Von Mises stress distribution and stress peak were calculated. The finite element model of normal TAS was basically consistent with biomechanics of the foot. According to biomechanical analysis, the maximum stress of the varus model appeared in the medial tibiotalar joint surface and the medial part of the top tibiotalar joint surface. The stress distribution of talofibular joint surface and the lateral part of the top tibiotalar joint surface were uniform. In the normal model, the stress distributions of the talofibular joint surface and the tibiotalar joint surface were uniform, and no obvious stress concentration was observed. The maximum stress in the 5° valgus model appeared at the posterior part of the talofibular joint surface and the lateral part of the top tibiotalar joint surface. The stress distribution of medial tibiotalar joint surface was uniform. The maximum stress of the 10° valgus model appeared at the posterior part of the talofibular joint surface and the lateral part of the top tibiotalar joint surface. The stress on the medial tibiotalar joint surface increased. With the increase of valgus, the stress of ankle joint gradually shift outwards, and the stress concentration tends to appear. There was no obvious obstruction of fibula with 10° TAS correction. However, when TAS correction exceeds 10° and continues to increase, the obstruction effect of fibula becomes increasingly significant.

Reconstructing avascular necrotic femoral head through a bioactive β-TCP system: From design to application

A variety of techniques have been used for treating avascular necrosis of the femoral head (ANFH), but have frequently failed. In this study, we proposed a β-TCP system for the treatment of ANFH by boosting revascularization and bone regeneration. The angio-conductive properties and concurrent osteogenesis of the highly interconnected porous β-TCP scaffold were revealed and quantified through an in vivo model that simulated the ischemic environment of ANFH. Mechanical test and finite element analysis showed that the mechanical loss caused by tissue necrosis and surgery was immediately partially compensated after implantation, and the strength of the operated femoral head was adaptively increased and eventually returned to normal bone, along with continuous material degradation and bone regeneration. For translational application, we further conducted a multi-center open-label clinical trial to assess the efficacy of the β-TCP system in treating ANFH. Two hundred fourteen patients with 246 hips were enrolled for evaluation, and 82.1% of the operated hips survived at a 42.79-month median follow-up. The imaging results, hip function, and pain scores were dramatically improved compared to preoperative levels. ARCO stage Ⅱ disease outperformed stage Ⅲ in terms of clinical effectiveness. Thus, bio-adaptive reconstruction using the β-TCP system is a promising hip-preserving strategy for the treatment of ANFH.

Design of porous structure based on the Voronoi diagram and stress line for better stress shielding relief and permeability

In the process of artificial metal bone implantation, the mismatch of elastic modulus and bad permeability behavior lead to obvious stress shielding and poor bone tissue ingrowth. For these problems, this paper proposed a new design method of the variable porosity porous structure based on the stress line and Voronoi diagram. In the design process, the principal stress line was determined by mechanical finite element analysis, which controlled the seeds distribution of the 3D Voronoi diagram, making local porosity conforms to the stress distribution. In addition, the designed samples were fabricated through laser powder bed fusion (L-PBF) technology with TC4 powders. The mechanical characteristics were evaluated by static mechanical simulation with ABAQUS and compression tests, and the permeability characteristics were analyzed by fluid simulation with COMSOL and in vitro and vivo test. The research results showed that the designed structure obtained the relatively low elastic modulus and higher mechanical strength, the designed structure has closer permeability characteristics to the reconstructed natural bone, and was conducive to cell proliferation. So the porous structure based on the stress line and Voronoi diagram might have good application potential in the bionic design of bone implants.

Subsidence Performance of the Bioactive Glass-Ceramic (CaO-SiO2-P2O5-B2O3) Spacer in Terms of Modulus of Elasticity and Contact Area: Mechanical Test and Finite Element Analysis

The objective of this study is to evaluate the subsidence performance of a bioactive glass-ceramic (CaO-SiO2-P2O5-B2O3) spacer in terms of its modulus of elasticity and contact area using mechanical tests and finite element analysis. Three spacer three-dimensional models (Polyether ether ketone [PEEK]-C: PEEK spacer with a small contact area; PEEK-NF: PEEK spacer with a large contact area; and Bioactive glass [BGS]-NF: bioactive glass-ceramic spacer with a large contact area) are constructed and placed between bone blocks for compression analysis. The stress distribution, peak von Mises stress, and reaction force generated in the bone block are predicted by applying a compressive load. Subsidence tests are conducted for three spacer models in accordance with ASTM F2267. Three types of blocks measuring 8, 10, and 15 pounds per cubic foot are used to account for the various bone qualities of patients. A statistical analysis of the results is conducted using a one-way Analysis of variance and post hoc analysis (Tukey's Honestly Significant Difference) by measuring the stiffness and yield load. The stress distribution, peak von Mises stress, and reaction force predicted via the finite element analysis are the highest for PEEK-C, whereas they are similar for PEEK-NF and BGS-NF. Results of mechanical tests show that the stiffness and yield load of PEEK-C are the lowest, whereas those of PEEK-NF and BGS-NF are similar. The main factor affecting subsidence performance is the contact area. Therefore, bioactive glass-ceramic spacers exhibit a larger contact area and better subsidence performance than conventional spacers.

Method of predicting valve seal leakage considering deflection of the spool

The small angular deflection of the spool under the action of non-equilibrium force is a main reason for valve seal failure. In the present study, a prediction model of the valve seal leakage was established considering the sectional shape and channel height of the leakage channel. The effect of spool deflection on the leakage rate was analyzed quantitatively from the results of three-dimensional finite element mechanical analysis. The microscale leakage channel of a contact deformation surface was then generated through the reconstruction of the rough surface with nanoscale precision, deterministic rough-peak contact analysis, and lattice leakage theory. The results showed that the spool deflection was the key factor affecting the leakage rate. The leakage rate was measured on a self-built experimental platform, and the experimental results verified the accuracy of the theoretical calculations.

A review of bioengineering techniques applied to breast tissue: Mechanical properties, tissue engineering and finite element analysis.

Female breast cancer was the most prevalent cancer worldwide in 2020, according to the Global Cancer Observatory. As a prophylactic measure or as a treatment, mastectomy and lumpectomy are often performed at women. Following these surgeries, women normally do a breast reconstruction to minimize the impact on their physical appearance and, hence, on their mental health, associated with self-image issues. Nowadays, breast reconstruction is based on autologous tissues or implants, which both have disadvantages, such as volume loss over time or capsular contracture, respectively. Tissue engineering and regenerative medicine can bring better solutions and overcome these current limitations. Even though more knowledge needs to be acquired, the combination of biomaterial scaffolds and autologous cells appears to be a promising approach for breast reconstruction. With the growth and improvement of additive manufacturing, three dimensional (3D) printing has been demonstrating a lot of potential to produce complex scaffolds with high resolution. Natural and synthetic materials have been studied in this context and seeded mainly with adipose derived stem cells (ADSCs) since they have a high capability of differentiation. The scaffold must mimic the environment of the extracellular matrix (ECM) of the native tissue, being a structural support for cells to adhere, proliferate and migrate. Hydrogels (e.g., gelatin, alginate, collagen, and fibrin) have been a biomaterial widely studied for this purpose since their matrix resembles the natural ECM of the native tissues. A powerful tool that can be used in parallel with experimental techniques is finite element (FE) modeling, which can aid the measurement of mechanical properties of either breast tissues or scaffolds. FE models may help in the simulation of the whole breast or scaffold under different conditions, predicting what might happen in real life. Therefore, this review gives an overall summary concerning the human breast, specifically its mechanical properties using experimental and FE analysis, and the tissue engineering approaches to regenerate this particular tissue, along with FE models.

Biomechanical effects of clear aligners with different thicknesses and gingival-margin morphology for appliance design optimization

The objectives of this study were to investigate the biomechanical effects of clear aligners (CAs) with various thermoplastic material thicknesses and gingival-margin designs for space closure in extraction treatment and to propose a computer-aided procedure to optimize CA design. The radiologic and intraoral scanning technology, invitro mechanical experiment, viscoelastic modeling, and finite element analysis (FEA) were integrated to establish an orthodontic simulation model. Twelve FEA models of CA were created, comprising combinations of 2 kinds of thicknesses (0.75 and 0.50 mm), 2 forms of gingival-margin shape (scalloped and straight), and 3 types of margin height (-2, 0, and 2 mm). Invitro testing was carried out to determine the actual properties of material thickness. A 0.75-mm-thick aligner resulted in greater periodontal ligament (PDL) stress than 0.50 mm, and there was no clear correlation between the control ability of tooth movement and the thickness. For different margin designs, PDL stress at -2 mm height was significantly lower than those with a higher border. Aligners with straight margins had higher stress than the scalloped aligners, whereas the differences were unnoticeable at 2 mm height. The optimized aligner with differential margin designs was recommended on the basis of biomechanical calculations, which facilitated the efficiency and control of tooth movement for multiple teeth. The effect of material thickness and margin design of CA on the force and movement differed in different teeth. Preferable CA designs of each tooth during different movement stages should be presented personalized under the guidance of precise biomechanics instead of pure morphologic analysis.

Lifetime modeling of solder joints based on accelerated mechanical testing and Finite Element Analysis

Lifetime modeling of solder joints based on accelerated mechanical testing and Finite Element Analysis