Static Simulation Research Articles

Multiscale analysis of recycled coarse aggregate concrete under the synergistic action of KH560 and PVA fibers

Considering the long-term working performance of the waste concrete building elements, this study used 3-Glycidoxypropyltrimethoxysilane (KH560) and Polyvinyl alcohol (PVA) fibers to modify the recycled concrete (RC) with the aim of improving the mechanical and long-term properties of RC. In this study, the mechanical properties of recycled coarse aggregate (RCA) concrete before and after modification were systematically investigated. The macroscale results showed that KH560 compensates for the reduced compressive strength of RCA concrete due to PVA fibers. The synergistic effect of PVA and KH560 substantially increased the flexural and shear strength of RCA concrete, with a maximum increase of 22.6% in flexural strength when the RCA substitution rate was 80%. The results of three microscopic tests (SEM / FTIR/XRD) revealed that KH560 increased the content of cement gel, which then optimized the internal pore structure of RCA concrete. The chemical reaction between KH560 and cement produced SiKH560-OKH560-SiCSH. At the nano-scale, computational analysis methods in atomistic modeling techniques were employed to model PVA fibers, cement and KH560, and the dynamic and static simulation results of the model were combined to discover a consistent SiKH560-OKH560-SiCSH chemical bond between KH560/CSH and both old and new CSH, Additionally, the findings revealed the coexistence hydrogen and ionic bonds. KH560 improves the interaction between PVA fibers and cement by forming numerous hydrogen bonds, and resolves the weak interface between the new and old cement through stable chemical bonds.

Analytical modelling with experimental validation of electromagnetic Halbach arrays in wireless power transfer systems

AbstractA mathematical model is presented for the optimisation of an Electromagnetic Halbach Array (EHA) for wireless power transfer. The mathematical model is based on Biot‐Savart's law of magnetic field in a current‐carrying square loop. The model is validated through static electromagnetic simulations in ANSYS Maxwell and found to be accurate and effective when predicting the magnetic field within the EHA box. To verify the analytical and simulation results, an EHA was fabricated, and experimental verification was carried out. The results show that the mathematical model can be widely used in the analysis and design optimisation of EHAs of any size and with diverse parameters in the case of single‐layer square spiral planar coils.

Time-dependent force depreciation of intraoral orthodontic elastics of variable force and lumen sizes – An in vitro study

: To evaluate force decay of elastics of different dimensions and different force values over 48-hours.Steps included extension and immersion of elastics in artificial saliva and measurement of force levels at a specified point of time. A model with vertical pins placed at in the oral cavity. The initial force measurement was done using Universal testing machine before the elastics were engaged onto the pins 37⁰C in artificial saliva. The reading was taken after this in the Universal testing machine for the samples. The elastics were then placed back into the static simulation for the next 23 hours and again into the dynamic simulation for the next 1 hour. Statistically significant difference (P<0.05) was observed between force depreciation between rest and maximum stretch of the elastic. Statistically significant difference was observed in force depreciation with varying time intervals of a particular elastic sample. Lumen size and pre-determined force values affect the overall force decrease pattern of elastics. Elastics with higher force and smaller lumen size show comparatively higher loss of force than the lighter elastics with larger internal diameter. The maximum force loss of a particular elastic happens within the first 24 hours of elastic stretch. The study would help provide information about how an elastic's lumen size and initial force are interdependent, giving clinicians a better understanding of how to prescribe the right elastics for the force they need to apply for treatment.

High-speed tracked vehicle model order reduction for static and dynamic simulations

In this paper, a model order reduction strategy is adopted for the static and dynamic behaviour simulation of a high-speed tracked vehicle. The total number of degree of freedom of the structure is condensed through a selection of interface degrees of freedom and significant global mode shapes, for an approximated description of vehicle dynamic behaviour. The methodology is implemented in a customised open-source software to reduce the computational efforts. The modelled tracked vehicle includes the sprung mass, the unsprung masses, connected by means of torsional bars, and all the track assemblies, composing the track chain. The proposed research activity presents a comprehensive investigation of the influence of the track chain, combined with longitudinal vehicle speed, on statics and vehicle dynamics, focusing on vertical dynamics. The vehicle response has been investigated both in frequency and time domain. In this last case road-wheel displacements are assumed as inputs for the model, under different working conditions, hence considering several road profiles with different amplitudes and characteristic excitation frequencies. Simulation results have proven a high fidelity in model order reduction approach and a significant contribution of the track chain in the global dynamic behaviour of the tracked vehicle.

3D crack propagation study of a railway component using XFEM method

This work develops a methodology to study the crack propagation through ABAQUS simulation. This simulation study uses the service condition of the mechanical component and the complex geometry of a manufacturing defect obtained by microtomography. It was concluded that the XFEM method is an essential tool in predicting crack propagation of a railway component. Furthermore, the type of criteria used in the XFEM method allowed the analysis of the propensity of the manufacturing defect to initiate crack propagation. The C3D4 elements were essential in realising the crack propagation simulation, considering a manufacturing defect. Having the pore’s complex geometry was crucial to developing the methodology presented in this study. The static analysis results indicated that the maximum stress concentration value in the pore is in a zone that can be identified as a hot spot. In addition, the pore showed a higher concentration of Von-Mises stresses than in the static simulation performed without a pore and of the material’s ultimate strength. In conclusion, the methodology presented in this work shows that developing a more realistic simulation study is possible. For a complete structural integrity study, the mechanical design simulation studies must include some complex geometries of intrinsic manufacturing defects.

Static versus dynamic muscle modelling in extinct species: a biomechanical case study of the Australopithecus afarensis pelvis and lower extremity.

The force a muscle generates is dependent on muscle structure, in which fibre length, pennation angle and tendon slack length all influence force production. Muscles are not preserved in the fossil record and these parameters must be estimated when constructing a musculoskeletal model. Here, we test the capability of digitally reconstructed muscles of the Australopithecus afarensis model (specimen AL 288-1) to maintain an upright, single-support limb posture. Our aim was to ascertain the influence that different architectural estimation methods have on muscle specialisation and on the subsequent inferences that can be extrapolated about limb function. Parameters were estimated for 36 muscles in the pelvis and lower limb and seven different musculoskeletal models of AL 288-1 were produced. These parameters represented either a 'static' Hill-type muscle model (n=4 variants) which only incorporated force, or instead a 'dynamic' Hill-type muscle model with an elastic tendon and fibres that could vary force-length-velocity properties (n=3 variants). Each muscle's fibre length, pennation angle, tendon slack length and maximal isometric force were calculated based upon different input variables. Static (inverse) simulations were computed in which the vertical and mediolateral ground reaction forces (GRF) were incrementally increased until limb collapse (simulation failure). All AL 288-1 variants produced somewhat similar simulated muscle activation patterns, but the maximum vertical GRF that could be exerted on a single limb was not consistent between models. Three of the four static-muscle models were unable to support >1.8 times body weight and produced models that under-performed. The dynamic-muscle models were stronger. Comparative results with a human model imply that similar muscle group activations between species are needed to sustain single-limb support at maximally applied GRFs in terms of the simplified static simulations (e.g., same walking pose) used here. This approach demonstrated the range of outputs that can be generated for a model of an extinct individual. Despite mostly comparable outputs, the models diverged mostly in terms of strength.

Joint angle prediction for a cable-driven gripper with variable joint stiffness through numerical modeling and machine learning

Soft grippers in automation, particularly those with variable joint stiffness, offer promising possibilities for precise manipulation tasks. However, accurately predicting finger joint bending angles in this field poses significant challenges due to the soft and complex nature of the grippers, making modeling and angle prediction difficult. This paper presents the development of a predictive model for precisely controlling bending angles in multi-material printed soft grippers with variable stiffness, which are pivotal for delicate manipulation tasks in automation. In particular, we explore a cable-driven gripper design made of thermoplastic polyurethane and conductive polylactic acid materials, featuring integrated resistive joints for stiffness modulation through controlled Joule heating. A data-driven modeling approach, combining numerical modeling of the gripper and machine learning techniques, was employed for the development of the predictive model. We performed static structural simulations using ANSYS Workbench to measure bending angles under various conditions for developing datasets for model training. In this work, we evaluated several machine learning models such as linear regression, decision tree, and K-nearest neighbor regression models to predict the correlation between temperature, pull distance, and bending angle. The K-nearest neighbor regression model demonstrated the highest accuracy, with a mean absolute error of approximately 11%. These findings underline the importance of precise angle prediction models in enhancing the functionality and reliability of soft grippers, paving the way for their broader application in automation and robotics.

Simulasi Kekuatan Mata Pisau Traktor Pemanen Jagung dengan Variasi Sudut Menggunakan Solidwork

The corn harvesting tractor is one of the innovations in agricultural technology. However, there is a problem where the harvesting blade is broken and wears out quickly. One of the factors causing the problem is the angle of inclination of the blade. The smaller the angle of inclination of the blade, the sharper it is but the risk of being easily broken and worn out. For this reason, it is necessary to test the value of the blade slope which has a good strength value. Before this knife is made directly, it is necessary to design and simulate the strength of the blade with a variety of angles. Experimental testing requires expensive costs and a lot of time. The simulation carried out is a static simulation with the finite element method in the solidwork application with AISI 1045 material and 87.05 N force load. The blade with an angle of 310 is the best angle with the maximum value of stress at the connection of the shaft and knife with a value of 20.664 MPa and the displacement results are at a maximum value of 0.018 mm.

Brazil’s New Gas Law: Analysis, Implications, and Remuneration of Gas Processing Plants with Non-Discriminatory Access to Customers

Brazil will increasingly rely on the availability of natural gas as new discoveries in the Pre-Salt portion are explored. Currently, a substantial amount of the gas produced associated with oil is reinjected (60,84 million m³/day in 2021, according to the Ministry of Mines and Energy), with the lack of structure being one of the factors for this non-energy purpose. The New Gas Law proposes to fill this gap by stimulating investments in infrastructure. In this sense, market opening has the potential to promote the rupture of natural monopolies by providing access to infrastructure, including Natural Gas Processing Plants (NGPP). This units, in addition to conditioning the gas for sale, allow the recovery of higher molecular weight fractions, or (Natural Gas Liquid). However, the instructions for this access required by the government are insufficient for issues related to the NGL recovery efficiency of these units, as well the method of remuneration arising from the NGL production capacity. It is proposed in this paper to include a processing tariff, based on static simulation of available technological routes. Comparison of energy spent and NGL recovery efficiency will allow to formulate the gas price, unfolding from the price of the molecule.

Effect of lattice type on biomechanical and osseointegration properties of 3D-printed porous Ti6Al4V scaffolds

Porous structure is an efficient tool for optimizing the elastic modulus and osseointegration properties of titanium alloy materials. However, the investigations on pore shape remain scarce. In this study, we created porous Ti6Al4V scaffolds with a pore size of 600 μm but different lattices (cubic pentagon, diamond, cuboctahedron). The mechanical and biological properties of the scaffolds were investigated in static simulation analysis, in vitro mechanical compression test, computational fluid dynamics, as well as cell and animal experiments. The results demonstrated that the calculated yield strength difference between the three Ti6Al4V porous scaffolds was negligible, at approximately 140 MPa, allowing them to match the strength requirements of human bones. The diamond scaffold has the lowest calculated elastic modulus (11.6 GPa), which is conducive for preventing stress shielding. The shear stress was largely concentrated in the diamond scaffold, and the stress range of 120–140 MPa accounted for the greatest share. The mouse MC3T3-E1 cells were found to attach to all three scaffolds, with the diamond scaffold displaying a higher degree of cell adherence. There was more proliferating cells on the diamond and cubic pentagon scaffolds than on the cuboctahedron scaffolds (P < 0.05). The diamond scaffold exhibited the highest alkaline phosphatase activity and calcium salt accumulation in cell differentiation tests. Besides, the expression of osteogenic genes on the diamond scaffold was higher than that on the cuboctahedron scaffold, the cubic pentagon scaffold displaying the lowest expression. The in vivo studies revealed that all three scaffolds fused well with the surrounding bone and that there was no loosening or movement of the prosthesis. Micro-computed tomography, corroborated by the staining results of hard tissues, revealed that the level of new bone formation was the highest in the diamond scaffold, followed by the cuboctahedron scaffold (P < 0.05). Taken together, the diamond scaffold is comparatively better at optimizing the elastic modulus and osseointegration properties of titanium alloy materials, and thus is a preferred choice for porous design.

Destruction and Protection Based on ANSYS Pile Foundations

In the process of pile foundation design and construction, pile foundation will produce different degrees of damage in order to protect the pile foundation from damage during the construction process. In this paper, three failure methods of pile foundation are analyzed by static simulation, namely the total deformation of the pile foundation, the maximum principal stress and the bending deformation of the pile body caused by excessive equivalent force. For the pile foundation, when the pressure value is between 2Mpa-3Mpa, the main stress, total deformation, and equivalent force of the pile foundation grow slowly, but when the pressure value exceeds 3Mpa, the deformation effect of the pile foundation increases significantly, and the distribution of the pile foundation is reasonably arranged in the later construction process to ensure that the pressure value of the upper part of the pile foundation is maintained at 2Mpa-3Mpa, so as to greatly reduce the damage of the pile foundation, of course, you can also use concrete materials with higher strength grades to reduce the deformation effect of the pile foundation and protect the pile foundation from being damaged.

Finite element analysis and clinical study of chest wall reconstruction using carbon fiber artificial rib

Carbon fiber composites are emerging as a promising new biomaterial for chest wall reconstruction implants due to their mechanical properties and biocompatibility. This work evaluates the biomechanics of carbon fiber artificial ribs using finite element analysis and clinical implementation. Static simulations of normal breathing process show the maximum stress on the implant is only 2.83 MPa, far below the material ultimate strength of 60 MPa, indicating the excellent fit for maintaining respiratory function. Dynamic collision simulations demonstrate the artificial rib model could withstand a 4 kg rigid object impact at 2 m/s without fracture. Reconstructing the artificial rib with a human rib in the finite element analysis model increases the overall stress tolerance. The impact force required for fracture increases 48% compared to the artificial rib alone, suggesting improved strength from rib integration. Clinically, 10 of 13 patients receiving the artificial rib implants show no significant loss of pulmonary function based on spirometry tests. Based on our findings, the combined simulations and clinical results validate the strong mechanical performance and biocompatibility of the carbon fiber artificial ribs for chest wall reconstruction under static and dynamic loading while maintaining normal respiratory function.

Evaluating Mechanical Strength in Vertical-Axis Tidal Turbines: A Comparative Study of Internal Blade Structure and Material Selection through CFD Simulation

Due to the density of water, tidal turbine blades are subject to significantly greater stresses than wind turbine blades. Multiple blade failures occurred during prototype testing as a result of loading conditions and protracted exposure to seawater, which created a severe work environment. The structural integrity of tidal turbine blades is essential for long-term reliability and performance. Numerous investigations into structural performance have been conducted. However, previous research has centred on horizontal-axis tidal turbines, while research on small-scale vertical-axis tidal turbines is limited. This paper aims to compare the Vertical-Axis Tidal Turbine (VATT) structural performance of hollow and solid blade structures in an identical NACA profile using three distinct materials. Finite element analysis (FEA) is employed to construct a model and simulate the mechanical characteristics of VATT blades. The use of static analysis simulation is employed in order to evaluate many parameters, including stress distribution and deflection. Parametric studies are conducted to explore the impact of internal blade structure and materials on mechanical strength. The use of computational fluid dynamics (CFD) simulations is employed for the purpose of analyzing the interaction between blades of vertical axis tidal turbines (VATT) and tidal currents, thereby enabling the assessment of structural loading. According to the simulation results, the hollow profile is subject to significant deflections and stresses. Other data indicates that the utilization of stiffeners in porous structures improves material efficiency and results in lighter blades, although further analysis is needed to investigate fatigue life prediction in optimizing structural design.

Structural and thermodynamic properties of the Li6PS5Cl solid electrolyte using first-principles calculations

We perform static and dynamic ab initio simulations to investigate the structural and the thermodynamic properties of Li6PS5Cl, a solid electrolyte actively considered for solid-state batteries. Our simulations account for...

Photoswitching of arylazopyrazoles upon S1 (nπ*) excitation studied by transient absorption spectroscopy and ab initio molecular dynamics.

Arylazopyrazoles (AAPs) are an important class of molecular photoswitches with high photostationary states (PSS) and long thermal lifetimes. The ultrafast photoisomerization of four water-soluble arylazopyrazoles, all of them featuring an ortho-dimethylated pyrazole ring, is studied by narrowband femtosecond transient absorption spectroscopy and ab initio molecular dynamics simulations. Upon S1 (nπ*) photoexcitation of the planar E-isomers (E-AAPs), excited-state bi-exponential decays with time constants τ1 in the 220-440 fs range and τ2 in the 1.4-1.8 ps range are observed, comparable to those reported for azobenzene (AB). This is indicative of the same photoisomerization mechanism as has been reported for ABs. In contrast to the planar E-AAPs, a twisted E-AAP with two methyl groups in ortho-position of the phenyl ring displays faster initial photoswitching with τ1 = 170 ± 10 fs and τ2 = 1.6 ± 0.1 ps. Our static DFT calculations and ab initio molecular dynamics simulations of E-AAPs on the S0 and S1 potential energy surfaces suggest that twisted E-isomer azo photoswitches exhibit faster initial photoisomerization dynamics out of the Franck-Condon region due to a weaker π-coordination of the central CNNC unit to the aromatic ligands.

Study on the influence of belt angle on tire grounding characteristics under longitudinal slip conditions

Using ABAQUS software as a tool and 225/60R18 tire as the research object, a finite element model of the tire was established and longitudinal slip simulation was conducted based on the completion of longitudinal slip and rubber material tests. By comparing the tire-pavement contact stress under longitudinal slip conditions with different angles of belt layers and the stress on the first belt steel cord, the influence of different angles of belt layers on the grounding characteristics of tires were analyzed. The results showed that under static loading conditions, the trend of tire-pavement contact stress presented a symmetrical “W” shape. Under dynamic longitudinal slip conditions, the tire-pavement contact stress curve was significantly different from the static loading simulation, with significant fluctuation and presented an irregular “W” shape, and asymmetric distortion occurred with the change of slip rate. At higher slip rates (±20%), the higher the asymmetry of the grounding imprint at the 61° and 63° belt layer angles. At the 65° belt layer angle, the ground imprint is more evenly distributed on the tread. The curve of stress variation on the belt steel cord along the path is in an “M” shape, and the stress on the belt steel cord is mainly distributed symmetrically on the tire-pavement contact surface corresponding to the tire shoulder position. The higher the slip rate, the higher the asymmetry of the stress distribution on both sides of the belt steel cord. At 65° and 67° belt angles, the distribution of grounding imprints on the tread are more uniform, and the tread is less prone to deformation, resulting in lower tread wear.

Development of a FEM procedure for evaluating the pressure profile in the industrial wheel and fatigue strength analyses

Industrial wheels are heavily loaded components that undergo severe cyclic stress conditions. Thus, the design of the rims must include a wide fatigue study which articulates in laboratory and field tests, analytical and numerical analyses and comparison of the experimental and computational results. This paper presents the study approach applied in the study of a 25 in rim for earth-moving machines manufactured by Moveero. The rim was subject to a design update which provided the reduction of the thickness from 11 mm to 9 mm. We decided to study the interaction tire-rim because it's a critical zone. The failures affected the area of the seat radius of the fixed flange of the rim, which resulted to be the most stressed part of the rim because of the bending actions of the tire on the flange. In order to deepen the cyclic mechanical behaviour of the component, laboratory inflation and rolling tests were carried out in Woodridge USA considering several combinations of inflation pressure and radial load applied to the wheel. The strain data from the tests were analysed to develop a reverse empirical model for the contact pressure between tire and rim. Once the load diagram applied to the flange for each test was estimated, FEM static simulations could be performed on a 3D model of the rim through SolidWorks Simulation. The stress fields obtained were then used for fatigue FEM numerical analyses which could return an evaluation of the predicted life of the component under several load conditions.

Influência da posição do sensor de sementes da semeadora em diferentes velocidades de trabalho

ABSTRACT: The uniformity of seed distribution and sowing speed directly impact crop quality and productivity. This experiment assessed how the position of the sowing monitoring sensor influences the distribution of cotton seeds using a pneumatic meter at different operating speeds. The experiment employed a completely randomized two-factor factorial design on a static simulation bench. The first factor involved the sensor installation sites (upper, middle, and lower portions of the conductor tube and conveyor belt), while the second factor encompassed simulated speeds of 3.0, 5.0, 7.0, 9.0, and 11.0 km/h. Parameters such as frequency of double, flawed, and acceptable spacing, coefficient of variation, and precision index were measured based on five replications of 250 consecutive spacing. The results indicated that the sensor’s placement significantly influences reading accuracy. Optimal results were observed when the sensor was positioned at the final portion of the conductor tube, providing more accurate seed deposition, and facilitating decision-making.

Influence of the ground motion directionality on the global ductility of 3D RC structures

This study examines the influence of ground motion directionality on global ductility μ_s of framed reinforced concrete structures. Suitable values of angle of attack θ, longitudinal reinforcement ratio ρ_l, dimensionless axial stress υ and mechanical ratio of transverse reinforcement ω_wd were assumed. Detailed nonlinear modeling was adopted to reproduce the behavior of reinforced concrete elements in the plastic field considering, also, the confinement effect on concrete mechanical properties. Nonlinear static simulations were carried out with the capabilities of the OpenSees code to evaluate the capacity curves and the corresponding global ductility. The results show that plastic hinges develop on the columns for the combined effect of bending moments transmitted by the beams framing into the same joint for values of the angle θ equal to 30° and 45°. Consequently, the formation of soft-storey mechanisms significantly reduces the global ductility μ_s. A design formula is proposed to avoid such collapse mechanism for framed reinforced concrete structures in ductility class high

Structural Reliability Analysis of Microsphere Focused Logging Tool Based on Response Surface Method

The push-pull system of microsphere focused logging tool is an important moving mechanism of this type of logging tool. The push-pull system will periodically bear large loads under working conditions and is prone to stress concentration. The structural strength reliability of the push-pull system is related to the logging accuracy and even the success or failure of the logging task. Based on ANSYS workbench software, this paper first conducts modeling and static simulation on the push-pull system of microsphere focused logging tool under working conditions, then conducts sensitivity analysis and experimental design on the basis of this analysis, and then conducts response surface analysis on the key stressed components of the push-pull system according to the analysis results. Finally, six sigma module is used to analyze the reliability of the push-pull system, and the structural strength reliability of the push-pull system is given by the probability distribution table obtained from the analysis. The analysis results show that the maximum equivalent stress occurs on the link arm of the push-pull system under working condition. The strength reliability of the link arm of the push-pull system under current working condition is high, and it can meet the daily logging requirements. However, there is still room for further design optimization.