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Cutting force analysis in milling processes is essential for precision metal cutting as it contributes to understanding tool wear, optimising machining performance, and ensuring overall process stability. Numerous research papers have been published to describe modelling techniques that provide high-fidelity predictions, with recent developments highlighting the benefits of combining different methods. However, these approaches are relatively limited in their ability to predict over the wide frequency range needed to describe the tooth passing frequency (TPF) and its harmonics under varying working conditions or stages of cutter-workpiece engagement (CWE). This paper studies the prediction performance of different modelling techniques when considering wide-band noise under varying working conditions. The methods evaluated are the explicitly defined but difficult-to-parameterise Finite Element Method (FEM), Semi-Analytical Solutions (SAS), and Long Short-Term Memory (LSTM) networks, which are black-box deep learning methods incorporating time-based information. Since white-box models are still more readily adopted by industry, the paper also introduces a new post-processing model to improve the prediction accuracy of FEM and SAS based upon the Fourier Series of the TPF (FS-TPF). Over the observable range of 0 to 1500 Hz, the cutting force predictability was assessed in both the time and frequency domains using similarity of frequency distribution, Shannon entropy, and Kullback–Leibler (KL) divergence. Verification and analysis indicate that the cutting force predictability with FEM at "partial engagement" was the lowest, due to its lack of ability to describe TPF harmonics. In contrast, the LSTM model showed the best prediction performance across all tested working conditions. The new FS-TPF significantly increased FEM's prediction accuracy by approximately 50% and improved SAS's performance by 20%. Finally, a Deep Neural Network (DNN) is compared to the LSTM, suggesting that both methods are suitable for force prediction without encountering significant accuracy issues across the different stages of CWE. It was found that the key to increasing cutting force predictability to be generally applicable to all milling conditions is the capability to describe TPF harmonics across the different CWE stages in milling processes. The FS-TPF compensation can dramatically enhance the cutting force prediction accuracy of FEM and SAS, while the applied DL-LSTM and DNN models have successfully demonstrated their wide adaptability without requiring additional post-processing. [ABSTRACT FROM AUTHOR]

Detection of biomarkers is exploited in lab-on-a-chip devices by means of Love type Surface Acoustic Waves (SAW). Finger type arrangement of electrodes, used for InterDigital-Transducers (IDT), perform well to create and detect SAW by using electro-mechanical coupling. Efficiency of such a transceiver depends on design parameters such as chosen material orientation, thickness, placement of electrodes. An optimized design reduces production costs, hence, we need a digital twin of the device with multiphysics simulations that compute deformation and electric field. In this study, we develop a framework with the open-source package called FEniCS for modal and transient analyses of IDTs by using the Finite Element Method (FEM). Specifically, we discuss all possible sensor design parameters and propose a computational design guideline that determines the "best" thickness parameter by maximizing mass sensitivity, thus, efficiency for a Love surface acoustic wave sensor. [ABSTRACT FROM AUTHOR]

The article discusses the use of integrated FEM-Multibody Co-Simulation to analyze the structural behavior of additively manufactured hip prostheses containing cracks. The study focuses on the mechanical properties of Ti-6Al-4V alloy, commonly used in hip replacements, and the impact of additive manufacturing on the porosity and elastic behavior of the component. The research aims to correlate defect propagation to premature failures in young and athletic patients, highlighting the importance of accurate numerical analysis techniques in predicting component reliability and failure mechanisms. [Extracted from the article]

In this paper, for the first time, the static bending and free vibration of bi-directional functionally graded (2D-FG) nanobeams partially resting on an elastic foundation are investigated. The nanobeams are composed of four material components and exhibit mechanical characteristics that vary smoothly and continuously along the thickness and length of the beam according to a power law. For the purpose of analysis, a finite element model is established using a two-node beam element, with each node having five degrees of freedom, combining Lagrangian and Hermitian shape functions. Based on a higher-order shear deformation theory and nonlocal theory, the governing equations of the 2D-FG nanobeams are derived using Hamilton's principle. Through the comparisons of the results obtained from the model with published results in the open literature, the accuracy and reliability of the present model are confirmed. Therefore, the proposed algorithm is compatible for predicting mechanical behaviors of nanobeams with arbitrary material distribution, various boundary conditions and complex loads. New numerical results are conducted to assess the influence of parameters such as volume fraction indexes, nonlocal parameters, foundation coefficients, length-to-height ratio and boundary conditions on the bending static and free vibration behaviors of the 2D-FG nanobeams. Especially, the role of the partial elastic foundations on the bending and vibration of the 2D-FG nanobeams is extensively investigated. [ABSTRACT FROM AUTHOR]

In this work, a novel quadrilateral four-node element capable of simulating the axisymmetric-torsion deformation of small-scale solids of revolution is developed based on the consistent couple stress theory (CCST). To establish the element formulation, the C1 requirement for displacement in the CCST is enforced in weak sense by using the penalty function method and the independent nodal rotation degrees of freedom are introduced into element construction to approximate the mechanical rotation fields. Besides, the stress functions that can satisfy the relevant equilibrium equation of the axisymmetric-torsion deformation are adopted as the basic functions for designing the element’s stress trial function. Several numerical tests are carried out and the results are compared to the solutions obtained using the analytical method or hexahedral solid element from the literature. It is shown that the new element exhibits good accuracy and captures the size dependences efficiently in prediction of the axisymmetric-torsion behavior of small-scale solids. [ABSTRACT FROM AUTHOR]

When a hydrogen storage vessel is subjected to a local impact load, damage may occur in the liner and result in hydrogen leakage and other catastrophic consequences. When predicting liner damage of a hydrogen storage vessel using the finite element method (FEM), although large element size is required to achieve a desired computational efficiency, it oftentimes causes inaccuracy in the damage model. To remedy this problem, in this study a novel approach which calculates the material damage based on the GISSMO (Generalized Incremental Stress State dependent damage Model) damage model and employs a submodeling strategy is proposed. According to this approach, the global model is discretized to large elements to increase the efficiency, while the submodel is meshed to much smaller elements to accurately reflect the material damage. Employing the established approach and material parameters calibrated from a large set of notched aluminum alloy 5083 specimens, the liner damage of a type III hydrogen storage vessel subjected to a local compressive load was simulated. This way, the study reveals how the characteristics of the stress and material damage interact with each other. In addition, the study also demonstrates that the proposed approach can be used as a viable means to evaluate the damage within hydrogen storage vessels. [ABSTRACT FROM AUTHOR]

Backgrounds/Objectives: The finite element method (FEM) is an advanced numerical technique that can be applied in orthodontics to study tooth movements, stresses, and deformations that occur during orthodontic treatment. It is also useful for simulating and visualizing the biomechanical behavior of teeth, tissues, and orthodontic appliances in various clinical scenarios. The objective of this research was to analyze the mechanical behavior of teeth, tissues, and orthodontic appliances in various clinical scenarios. Materials and Methods: For this study, we utilized a model derived from a set of CBCT scans of a 26-year-old female patient who underwent fixed orthodontic treatment using the lingual technique. Through a series of programs based on reverse engineering, we constructed a three-dimensional reconstruction of the teeth and their internal structures. Using the finite element method (FEM), we obtained six simulations of an orthodontic system utilizing the fixed lingual technique, in which we employed brackets made of chrome–nickel or gold, and archwires made of nitinol, gold, or stainless steel. Results: The study reveals that although the deformation of the archwires during orthodontic treatment is the same, the forces generated by the three types of archwires on brackets differ. The variation in forces applied to the brackets in the fixed lingual orthodontic technique is essential for customizing orthodontic treatment, as these forces must be precisely controlled to ensure effective tooth movement and prevent overloading of the dental structures. Conclusions: The FEM analysis allows for the identification of ideal combinations between the materials used for orthodontic archwires and the materials used for brackets. This ensures that the optimal intensity of forces applied during the fixed lingual orthodontic technique results in desired tooth movements without causing damage to the enamel, dentin, or pulp of the teeth. [ABSTRACT FROM AUTHOR]

The curing distortion is a critical determinant of the quality of integrally manufactured composite structures, playing a pivotal role in the design and fabrication of composite. This paper presents two simplified methods in predicting the curing distortion for large-scale composite aircraft structures manufactured through the autoclave process. Firstly, the refined finite element models of the two simplified methods were developed. Then, it was utilized to predict the curing distortion of Ω-shaped composite laminates. The comparative study between the experimental data and numerical results shows that the proposed second simplified method balanced the prediction accuracy and efficiency, which is urgently needed in practice. Finally, using the second simplified method, predictions were conducted for the curing distortion of practical large-scale composite skin structures. The results were in good agreement with the corresponding experiments. This study provides a new solution for the rapid iterative design of large-scale composite structures, as well as the efficient design of frame molds for their manufacturing. [ABSTRACT FROM AUTHOR]

The paper presents the results of experimental and numerical tests on barrel vaults with backfill material. The thickness, internal span, and rise of the vaults were 125 mm, 2000 mm, and 730 mm, respectively. In experimental studies, vaults with backfill of expanded clay aggregate or granite aggregate were tested. Moreover, three types of extrados finishing were considered in the experiments: masonry with flush joints, PVC film, and steel angles attached to the bricks. The numerical simulations increased the number of cases analyzed by conducting a parametric analysis for four additional backfill materials with varying bulk density or internal friction angle, as well as modifying the friction coefficient at the backfill-vault interface for each of the analyzed materials. The main goal of the analyses was to investigate the impact of the bulk density, the internal friction angle of the backfill material, and the friction coefficient between the backfill and the vault on the load-bearing capacity of the buried vault. Both the laboratory tests and numerical simulations indicate a significant impact of the internal friction angle, bulk density of the backfill materials, and the finishing method of the extrados of the vault on the load-bearing capacity of buried vaults. [ABSTRACT FROM AUTHOR]

This paper provides a comprehensive evaluation of using 3D-printed composite molds to produce components for the automotive sector in carbon fiber-reinforced polymers (CFRPs). Two molds in Carbon PA, i.e. PA6 reinforced with 20% by weight short carbon fibers, were realized via fused filament fabrication and subjected to multiple thermal cycles to simulate successive curing operations. Mold distortions were measured using a coordinate measuring machine before and after each heat treatment. Additionally, finite element method (FEM) and life cycle assessment (LCA) analyses were performed to obtain a complete overview of the 3D printed mold use and provide an industrial decision-making tool. Results showed that the mold distortion increases with temperature, and the clamping effect is more pronounced at the mold's edges, and it is reduced in the center. Irrespective of the thermal cycle temperature, the highest distortion was observed on the upper surface, with reduced deformation on the composite layup plane. FEM simulations confirmed that, following bolt tightening, the molds can resist without critical stress or plastic deformation. LCA analysis demonstrated that 3D-printed molds reduce environmental impact by 18% compared to aluminum ones, leading to more sustainability benefits for low-volume production, making them ideal for prototyping, small batches, or customized components. The potential of 3D-printed molds as a valid alternative to traditional methods to produce low-volume CFRPs was demonstrated. The implications of this study highlight the efficiency and sustainability benefits of 3D printing technology in composite manufacturing, offering a flexible solution for industries where small production runs and customization are critical. [ABSTRACT FROM AUTHOR]

Functionally graded materials with their structural characteristics, such as the type of distribution, the size of phases, gradually change from one surface to another and provide a wide range of applications. In this research, the optimization of geometric parameters of FG structure rested on the elastic foundation, including damping effects is of interest. The cylindrical shell's material properties are assumed to vary smoothly and continuously across the thickness according to the power law distribution of the volume fraction of constituents. The governing equations of stiffened functionally graded cylindrical shell resting on an elastic foundation are obtained using Hamilton's principle, the first-order shear deformation theory and finite element method. The numerical results are obtained for studying the effect of various factors, such as distribution of volume fraction, length and thickness, different boundary conditions, stiffness and damping coefficients, and also the natural frequency of the dynamic responses of the cylindrical shell. The damping effects are considered which were not presented in previous studies. The frequency responses of the cylindrical FGM shell resting on elastic foundation were obtained by adding the damping term into the governing equations. Besides, analytical formulation results were considered as an objective function (input) for optimization in Genetic Algorithms. Finally, the compatibility of the analytical modeling results with the commercial finite element software was checked which showed good agreement. [ABSTRACT FROM AUTHOR]

Featured Application: Magnetic FEM analysis results for quasi-static cases can be used in dynamic simulations through Look-Up Tables, which reduce the computation time. This study presents the design and analysis of a proportional solenoid used in electro-pneumatic brake systems for heavy vehicles. The solenoid was designed using a traditional method, and its static and dynamic characteristics were investigated both theoretically and experimentally. ANSYS 2024 R1 Maxwell was employed for theoretical static analysis, focusing on the effects of the geometric dimension parameters in the fixed and moving pole contact regions on the force–displacement characteristics. The optimal dimensions for proportionality were determined under constraint parameters. The static analysis results provided the magnetization curve data, which were used to create Look-Up Tables for a dynamic model in MATLAB R2024b-Simulink, and this method reduced the simulation time and increased the dynamic simulation accuracy. Following static analysis, a prototype electromagnet was manufactured and tested. The solenoid achieved a constant magnetic force of 45 ± 3 N with a current of 1.3 A over a working range of 1–3 mm. The dynamic model, incorporating data from ANSYS, yielded results that closely matched the experimental findings. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical properties of Glass Fiber-Reinforced Plastic (GFRP) pipes in the circumferential direction using the split-disk method, with a focus on understanding the influence of aggressive environmental conditions. The split-disk method was used to determine the key mechanical properties, including the hoop tensile strength and modulus, and also the Poisson's ratio, which are critical for the performance of GFRP pipes under internal pressure. The experiment was conducted under controlled laboratory conditions, and the results were analyzed to assess the effects of exposure to aggressive environments (saltwater and alkaline solutions at 20 °C and 50 °C). The correlations between the UTS, elastic modulus, and Poisson's ratio highlight how GFRP pipes degrade under environmental exposure. As the UTS decreases, so do the stiffness and lateral deformability, with the most significant reductions occurring in chemically aggressive environments at high temperatures. Exposure to an alkaline solution weakens the GFRP pipes, with the strength dropping more sharply at higher temperatures, with the UTS decreasing by 21%. Saltwater exposure reduces the elastic modulus, especially at higher temperatures, with a 14% decrease, accelerating material degradation and reducing deformation resistance. An alkaline solution further lowers the modulus, with a 21% decrease at 50 °C, showing the lowest stiffness. Air exposure, in contrast, has a less severe effect, with the pipes retaining much of their mechanical integrity. These findings collectively suggest that environmental degradation affects the overall mechanical behavior of GFRP pipes, providing valuable insights for the design and maintenance of GFRP piping systems, particularly in industries where exposure to aggressive environments is common. This study underscores the importance of considering environmental factors in the material selection and design processes to ensure the long-term reliability of GRP pipes. [ABSTRACT FROM AUTHOR]

Steel is an important construction material in civil engineering. In addition, the building industry is one of the global economy's largest sectors, responsible for one-third of the energy consumption and significant CO2 emissions. For this reason, there is a need to design effective structures that are characterized by the lowest possible steel consumption. This article presents an approach to sustainability considerations in steel structures, namely the approach of shaping efficient steel canopies with modular roofs using genetic algorithms. The shed structures, which were designed based on a regular polygonal plan, were constructed from grid modules that were formed on the basis of the hyperbolic paraboloid (HP) units arranged radially, supported by the columns, and covered by metal sheets. The algorithmic definitions allowed for the creation of numerous variants of the structures with the adopted preliminary criteria and for the performance of genetic optimization in order to select the best results. Twenty-four kinds of structures were analyzed and compared, differing in the quantity of modules, module shapes, arrangements, and dimensions. This made it possible to observe changes in the efficiency of the structures depending on the form of the roof applied. As a measure of structural efficiency, the coefficient representing the mass of the shed structure per square meter of the covered area was utilized. The presented design approach and optimal solutions can be helpful in shaping more complex sustainable structures, for which the analyzed sheds constitute modules. [ABSTRACT FROM AUTHOR]

Sparse linear system solving is a primary computational cost in large-scale finite element analysis, and improving its performance is a key technological challenge in this field. Real-world engineering problems involve diverse materials, elements, and connectivity relationships, making it difficult for iterative methods to handle their global stiffness matrices. Direct methods, owing to their robustness, emerge as the preferred choice. In this paper, a novel block-based supernodal LDLT numerical factorization method is introduced. The computational process is disassembled into distinct tasks, and the dependency relationships between these tasks are expressed via a directed acyclic graph to guide the calculation sequence. Based on this approach, a global task pool and local task stack are established to store task queues, enhancing data reuse and multicore collaboration efficiency. Additionally, an effective task dispatch and work-stealing mechanism is implemented to prevent performance degradation caused by load imbalances. Numerical experiments, including a publicly available matrix test set and real-world engineering finite element problems, are conducted to compare the parallel performances of the Pardiso, MUMPS, and proposed solver. The results illustrate that the proposed solver performs significantly better than the other solvers when handling various types of sparse matrices and diverse architectures of multicore processors. [ABSTRACT FROM AUTHOR]

This paper discusses novel numerical techniques for studying the damage to automotive safety components in carbon fiber reinforced polymer (CFRP) deployed in the automotive industry to protect passengers, high voltage batteries and powertrains from rear impacts. The idea proposed in the manuscript is to use Newmark's methodology with the FEM for the numerical description of the explicit dynamic model of the components facing the standard impactor, following the Euro NCAP protocol. Using an explicit dynamic Radioss rear crash box, we have successfully demonstrated normal behavior for CFRP materials, where the value of kinetic energy is close to the theoretical value. Moreover, the simulation provides a behavior consistent with previous successful studies because the maximum dynamic time is the same as the total damage (0.10 ms). [ABSTRACT FROM AUTHOR]

A theoretical model for porous viscoelastoplastic (VEP) materials in the dry state is investigated in this research study. The model is based on the principles of conservation of mass and energy using the rheological dynamic theory (RDT). The model provides expressions for the creep coefficient, Poisson's ratio, modulus of elasticity, damage variable, and strength as a function of porosity and/or void volume fraction (VVF). The reliability of the proposed model was analyzed by comparing numerical results with experimental ones on hardened concrete. A numerical model was created and analyzed in the commercial software Abaqus and validated by comparison with experimental data obtained by geodetic measurements on a composite wood–lightweight concrete girder. The deflections and stresses of the beam resulting from the influence of concrete creep and porosity were analyzed at the initial moment of time and after 6 years. The results showed that the RDT provided a reliable model for estimating parameters after exposure to long-term loads. [ABSTRACT FROM AUTHOR]

The basis of describing stress intensity factor and predicting residual life of structure is the right numerical model of dynamic crack propagation. 'FEM+M integral' and 'XFEM+M integral' methods were, respectively, adopted. Difficulties of 'FEM+M integral' method were solved, such as the singularity of crack tip, nodal uncoincidence of rubber layer unit and plate unit during mesh repartition and calculation convergence. In addition, difficulties of 'XFEM+M integral' method were overcome, such as difficult crack tip coordinates, difficult cutting point of crack and element and crack deflection in the element. On this basis, the effective calculation of stress intensity factor was realised. Through simulation and calculation, it is found that the error value is within 5%. The model reliability is further verified within the allowable error range. [ABSTRACT FROM AUTHOR]

The mechanical performance of joints for any engineering applications requires accurate characterization of joint interfaces. This paper presents a simplified experimental procedure to estimate the cohesive zone model (CZM) parameters for predicting the interface failure of adhesively bonded joints subjected to mode I (opening) and mode II (shear) loading. The novelty of this procedure lies in predicting all CZM parameters—cohesive stiffness, strength, and cohesive energy (fracture toughness), of the bonded interface using one common experimental setup. It is observed that the cohesive strength and cohesive energy in shear loading are approximately 3.8 and 11.6 times, respectively, compared to the opening loading condition. Employing a triangular cohesive law, the CZM parameters are combined with appropriate damage initiation (quadratic stress) and evolution (power law) criteria. The proposed methodology is verified against experimental load–displacement responses of the bonded interface under mixed‐mode I/II (opening/shear) loading across a wide range of mode mixity (α = 0°, 15°, 30°, 45°, 60°, 75°, and 90°). The maximum error between the experimental and the numerical peak load is 5.11%. The acceptable agreement between the numerical and experimental results confirms the effectiveness of this method in investigating interface fracture in adhesively bonded joints under different loading conditions. [ABSTRACT FROM AUTHOR]

The 2022 Paktika earthquake (moment magnitude: 6.2) occurred on June 22, 2022, near the border between the Khost and Paktika Provinces of Afghanistan, causing heavy damage and casualties in Paktika Province. This study evaluated the crustal deformation and associated strong motions induced by the Paktika earthquake. Crustal deformations were determined using the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique and three-dimensional finite element method (3DFEM) and the results were compared. The permanent ground displacements obtained from the DInSAR and 3D-FEM analyses were similar in terms of amplitude and areal distribution. Strong motions were estimated using the 3D-FEM with and without considering regional topography. The estimations of maximum ground acceleration, velocity, and permanent ground deformations were compared among each other as well as with those inferred from failures of some simple structures in the Spera and Gayan districts. The inferred maximum ground acceleration and velocity from the failed adobe structures were more than 300 Gal and 50 cm/s, respectively, nearly consistent with the estimates obtained using empirical methods. The empirical method yielded a maximum ground acceleration of 347 Gal, whereas the maximum ground velocity was approximately 50 cm/s. In light of these findings, some surface expressions of crustal deformations and strong ground motions, such as failures of soil and rock slopes and rockfalls, have been presented. The rock slope failures in the epicentral area were consistent with those observed during various earthquakes in Afghanistan and worldwide. [ABSTRACT FROM AUTHOR]

This study addresses the critical need for optimizing heat transfer and fluid flow in porous ring structures, which are essential for various thermal management applications. The aim is to investigate how different parameters such as obstacle length(B), heat source position(D), heat generation coefficient(Q), Hartmann coefficient (Ha), porosity(ε), and Rayleigh coefficient (Ra) affect heat transfer and fluid flow characteristics in a porous ring structure with multiple heat sources. The modeling assumes steady-state conditions, isotropic and homogeneous porous media, and uniform heat generation within the obstacles. Finite Element Method (FEM) simulations were employed to analyze the effects of the aforementioned parameters on streamline distributions, temperature profiles, and heat transfer rates. Remarkably, increasing obstacle length and higher porosity generally enhance heat transfer efficiency, while positioning heat sources closer to the outer boundary and higher Rayleigh numbers lead to reduced heat transfer. The study reveals that, contrary to conventional expectations, various parametric changes consistently result in decreased heat transfer, making the porous ring structure suitable for applications requiring thermal isolation or minimized heat leakage. [ABSTRACT FROM AUTHOR]

Analysis of structures is done in two ways reliance matrix and stiffness matrix methods. In the soft method, the unknowns of the problem are forces. In the soft methods, we need an additional equation for the number of statically indeterminate degrees. In our hardness method, the unknowns are the deformation of the structure, and after obtaining them, the unknown forces of the structure can be obtained. Also, for structures that have a low degree of uncertainty but a high degree of freedom, the soft method is easier, but for structures that have a low degree of freedom, the hard method is good. In this article, we have investigated the structure related to the pipelines of a station, such as the gas pressure boosting station, using the stiffness method. Pipeline systems under thermal loads are frequently used in many systems are relate to in oil and gas like power stations or pumping houses and petrochemicals and gas stations. Unlike the analytical center of elastic method, which can analyze only a single branch of pipeline with members the coordinate system installed parallel to the pipe, the stiffness method removes these kinds of limitations. In this article, the stiffness method is introduced to analyze pipeline systems. Based on this method, the piping system may include any numbers of pipe branches. The straight elements of pipe in the branch may have any general orientation, and the bend elements may have any arbitrary angle. The computer program designed based on this method may compute the nodal displacements at the ends of the straight or bent elements and present three components for loads and three for moments. Once the free-body diagram of each piping element with nodal forces and moments is drawn, the engineering codes are employed to design the piping system for safe operation. By using this method every kind of pipelines including constraint and unconstraint could be analysed. As we know in powerplant and pipeline systems, thermal stresses are one of the major problems. Every year this phenomenan cause many damages for industries then computing and predicting the effect of thermal loads are very essential for engineeres. Stiffness method is a general and simple method for computing nodal forces for piping or pipeline systems and every kind of pipelines with any geometric plan and every number of branch of pipes. Maximum forces and moment could be computed in every point of system and then the best position for installation of hangers and foundations can be determined. [ABSTRACT FROM AUTHOR]

A comprehensive model for evaluating the functionality of a multi-gear pump has been developed. The integrated model for assessing the functionality of a multi-gear pump contains a computational fluid dynamics analysis (CFD) model combined with a finite element method (FEM)-based strength model. Two submodels were linked: a CFD submodel to evaluate the internal pressure distribution of the pump and a structural FEM submodel to calculate the stresses and structural displacements of the pump due to fluid pressure. Finite element analysis in SolidWorks 2016 was used to evaluate the strength of the gear joints of the pump gears. As the pressure of the working fluid increases from 6 to 20 MPa, a linear increase in Mises stresses is observed. At the shaft, these stresses increase to 226.2 MPa, and at the tooth mouths, they reach a maximum value of 205.5 MPa. With the increase in torque on the drive shaft from 100 to 500 N·m, there is a significant increase in Mises stresses localized in the contact zones of the shaft with the drive gear. Analysis of the data obtained showed that the displacements caused by the pressure of the working fluid are insignificant compared to the displacements arising under the action of torque. With increasing pressure and torque, there is a tendency to decrease the safety factor, which indicates a decrease in the safety factor of the design of the multi-gear pump. The safety factor is not provided at a torque of 400–500 N·m. The simulation results are confirmed by correlation analysis. The average approximation error is 5–7%. [ABSTRACT FROM AUTHOR]

Debris flows are a dynamic and hazardous geological phenomenon, as by definition, debris flows are rapid, gravity-driven flows of saturated materials that often contain a mixture of water, rock, soil, and organic matter. They are highly destructive and occur in steep channels, posing a significant threat to infrastructure and human life. The dynamics of debris flows are complex due to their non-Newtonian behaviour and varying sediment–water interactions, making accurate modelling essential for risk mitigation and emergency planning. This paper reports and discusses the results of numerical simulations of back analyses aimed at studying the reconstruction of a real rapid debris flow. The selected test case is the event that occurred on 12 and 16 March 2021 along the Rio Sonno channel, a tributary of the Liri River, following the landslide event of Rendinara (Municipality of Morino, Abruzzo Region, Italy). There are significant flow sources in the area, fed by a highly fractured carbonaceous aquifer that extends immediately upslope of the detachment zone. The continuous flow influences the saturation level in the fine-grained sediments and favours the triggering of the debris flow. This phenomenon was simulated using the commercial RAMMS code, and the rheological model selected was "Voellmy fluid friction". The modelling approaches used in this research are valid tools to estimate the volumes of materials involved in the flow-feeding process and for the purpose of possible mitigation works (debris flow-type dams, weirs, flow diversion, etc.). [ABSTRACT FROM AUTHOR]

Alignment deviations remain one of the main causes of excessive vibration amplitudes among all rotating equipment. Their influence is particularly noticeable in ship shaft lines since their length is often much greater than their diameter. Dial gauges and laser measuring instruments are the most commonly used methods for measuring the alignment deviations of ship shaft lines. Due to the increasingly common use of vibration diagnostics in shipbuilding, it is necessary to develop methods to identify shaft misalignment using vibration methods. The authors of this study identified the spectra components corresponding to the misalignment of a working test station of a ship's shaft line. Identification was carried out in two stages: based on an analysis of the FEM model using the Abaqus program and based on measurements on a unique laboratory stand. The obtained results confirm the possibility of using FEM simulations in the operational diagnosis of shaft line alignment deviations. [ABSTRACT FROM AUTHOR]

In order to solve the dietary problems of patients with dysphagia, a mathematical model for predicting extrusion pressure is established. The predictive model parameters are determined with the aid of the finite element method, and a 3D printing nozzle capable of printing nutrient-rich sandwich food is designed according to the predictive model. Pumpkin puree and minced pork are verified according to IDDSI standards. Finally, the accuracy of the predictive model and the printing effect of the design nozzle are verified by extrusion and printing experiments, respectively. The results show that four groups of simulation experiments reveal that the extrusion pressure increases by 15.6%, 13.5%, 12.7% and 12.4%, respectively, with a 1 cm increase in nozzle length. When the nozzle length is in the range of 1–5 cm, the extrusion pressure increases with the increase of the volume flow rate in the extrusion cylinder. The extrusion speed has little correlation with the length of the nozzle outlet, but for every 1 cm3/s increase in the inlet volume flow rate, the extrusion speed increases by about 1.5%. The finite element simulation experiment determines that the parameters of the prediction model are σ0 = 0.6, α = 1.1, m = 0.21, τ0 = 0, β = 0.52 and n = 0.2; the error between the predictive value and the experimental value is 15%, and the printed sandwich food has smooth lines, good molding and complies with IDDSI standards. [ABSTRACT FROM AUTHOR]

Friction is a critical influencing factor for a variety of forming processes, as it affects, for example, the required forming force. Complex models for the numerical description of friction often have two or more model parameters but lack appropriate calibration methods since calibration schemes developed for one-parameter models are not applicable. The objective of this work is to develop an evaluation method based on inverse modeling of the conical tube-upsetting test in order to allow for the parametrization of a two-parameter friction model, providing a unique solution for the model parameters. It is based on a comparison of the specimen's outer contour for several points in time throughout the forming process according to the finite element model of the test. An optimization algorithm minimizes the deviation between the experimental and the simulated contour by adapting the friction model parameters. A two-parameter model is used that considers normal stress as well as relative velocity. First, purely numerical investigations show the necessity of a model adaption due to insufficient data. The modeling scheme is therefore adapted to consider data from two tests with different relative velocities. The results suggest a unique solution for the determination of the friction model parameters for purely numerical studies as well as for experimental conditions, comparing with the evolving contour of the conical tube-upsetting test specimen. Thus, this study presents a promising approach for the calibration of two-parameter friction models. [ABSTRACT FROM AUTHOR]