This research paper focuses on conducting a steady state seepage analysis along with the downstream slope factor of safety using the Modified Bishops method in a poorly compacted earthen embankment ...and optimizing the same reservoir earthen embankment in a case study located near Sadiyavav village in Junagadh district in Gujarat, India. The study site, situated at 21°32'06.5"N and 70°37'26.7"E, is renowned for its Asiatic lions. The analysis and optimization were performed with a double-textured High-Density Polyethylene (HDPE) Geo-membrane barrier. Previously, designs and numerical solutions proposed homogenous embankments and too poorly compacted with no drainage arrangements, which led to anisotropic conditions within the section and water seeping out, cutting the phreatic line. The paper presents the documented improvements in the factor of safety achieved through the seepage analysis and the optimization of the HDPE Geo-membrane barrier. Two improvement techniques were studied using the “Limiting Equilibrium-Finite Element Method” (LS-FEM). The first using (HDPE) Geo-membrane stabilized with gabions, and the second alternative using HDPE Geo-membrane with gabions in addition to rock toe. The study results showed improvements in the downstream slope stability for the two alternatives by 3% and 10%, respectively. Doi: 10.28991/CEJ-2023-09-11-07 Full Text: PDF
The behavior of a piezoelectric element can be reproduced with high accuracy using numerical simulations. However, simulations are limited by knowledge of the parameters in the piezoelectric model. ...The identification of the piezoelectric model can be addressed using different techniques but is still a problem for manufacturers and end users. In this paper, we present the use of a machine learning approach to determine the parameters in the model. In this first work, the main sensitive parameters, c11, c13, c33, c44 and e33 were predicted using a neural network numerically trained by using finite element simulations. Close to one million simulations were performed by changing the value of the selected parameters by ±10% around the starting point. To train the network, the values of a PZT 27 piezoelectric ceramic with a diameter of 20 mm and thickness of 2 mm were used as the initial seed. The first results were very encouraging, and provided the original parameters with a difference of less than 0.6% in the worst case. The proposed approach is extremely fast after the training of the neural network. It is suitable for manufacturers or end users that work with the same material and a fixed number of geometries.
Vacuum conveyor belt punching process by using the piercing punch which cooperates with the die has potential to be modified in aspects of lowering the perforation force, extending the tool life, and ...improving the hole quality in the perforated belts. All these parameters have an influence on the efficiency of the process and strictly depends on the punch geometry. This indicates that based on these criteria the optimization of the tool constructional features may be performed. In the presented research, authors have shown the linear correlation between the resistance force of the compressed material of the multilayer polymer composite belt in punching and the efficiency of the process. It was also proved that using the effective geometry of the piercing punch with spherical bowl can reduce the perforation force by 69%. Based on the obtained model, the simplified optimization as well as the evaluation of the punches with defined geometry can be performed, since all characteristics of the material compressive force obtained for the effective punches were almost consistent. For proper analysis, it is necessary to use the combination of the analytical and numerical modelling, computer simulations with using the finite element method (FEM) and the experimental tests. However, by performing simple compression tests for various tool geometry on the strength testing machine, it is possible to perform the comparison analysis of different piercing punches based on the derived models. This approach can be used to evaluate the properties of selected tools for the groups of materials with wide divergence of the mechanical properties without performing the complex research.
This paper presents a novel finite element method (FEM) of optimization for driving frequency in magneto-mechanical systems using contactless magnetoelastic torque sensors. The optimization technique ...is based on the generalization of the axial and shear stress dependence of the magnetic permeability tensor. This generalization creates a new possibility for the determination of the torque dependence of a permeability tensor based on measurements of the axial stress on the magnetization curve. Such a possibility of quantitative description of torque dependence of a magnetic permeability tensor has never before been presented. Results from the FEM-based modeling method were validated against a real magnetoelastic torque sensor. The sensitivity characteristics of the model and the real sensor show a maximum using a driving current of similar frequency. Consequently, the proposed method demonstrates the novel possibility of optimizing magnetoelastic sensors for automotive and industrial applications.
In this work, the development of a hybrid lightweight automotive chassis control arm is demonstrated. It includes the development of a new simulation method for designing metal — LFT (long ...fiber-reinforced thermoplastics) rehybrid parts and the new hybrid forming method for its manufacture. Beginning with the original geometry of a series steel chassis control arm, the design was optimized for the hybrid forming process where a steel sheet part is reinforced by an LFT rib structure, and both parts are joined by an LFT layer. For this purpose, a new FE optimization process chain was established. The thickness of the sheet metal and LFT layers, the geometry and thickness of the ribs of the hybrid control arm could be determined to meet both mechanical and light weight requirements. Afterwards, a suitable tooling concept and process for the hybrid forming were developed and tested. The forming behavior of two different steel grades along with an LFT was demonstrated and analyzed with the help of 3D measurement techniques and relevant section cuts. Finally, a weight reduction of nearly 20 % compared to the original component was realized with the hybrid forming process.
Soft tissue characterization with the inverse finite element method (FEM) optimization algorithm plays an important role in developing a physical model for medical simulations. However, tissue ...characterization that takes into account comprehensive boundary conditions for large deformations remains a challenge due to computational complexities and a lack of experimental data. In this study, soft tissue experiments on porcine livers were performed to measure the surface deformation and force response of soft tissues resulting from indentation loading depending on various indentation depths and two different tip shapes. Measurements were carried out with a three-dimensional (3D) optical system and a force transducer. Using the surface deformation and force response results, we estimated the maximum radius of influence, which can be utilized to determine the minimal required soft tissue model size for the FEM simulation. Considering the influence of the boundary conditions, the model was designed and integrated into an inverse FEM optimization algorithm to estimate the model parameters. The mechanical behavior of large deformations was characterized with FE modeling via hyperelastic and linear viscoelastic models.
In food process simulation studies, geometrical characterization of agricultural produce is extremely difficult due to their irregular shapes. Further simplifications and assumptions can be applied ...to overcome this problem. Also, applying 3D scanners may easily and realistically lead to more accurate results from simulations. The aim of this work was to study this discrepancy in the obtained values of the elastic parameters of organic materials under a compression case using a finite element method and experimental data. The Zaria variety of pumpkin seed was chosen as a typical sample of an organic material. A 3D scanner, high speed camera, and simulations using a finite element method were used to investigate modulus of elasticity, force, energy, and stress distribution of the pumpkin seed under the condition of parallel plate compression. The results of a compression test were used as experimental analysis. The force/deformation curve generated by the finite element method modeling matched the curve from the experimental test remarkably well up to 0.9 mm combined deformation and showed that the finite element method can be used to describe accurately mechanical behavior of pumpkin seed under compression.
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•A combined FEM optimization of GPS and GPS/acoustic data improves the quality of the slip distribution at the fault plane.•The fault slip distribution explains the recorded dataset ...without claiming for zones with inelastic properties.•The boundary position of the polar reversal of the vertical displacements expected from the upper plate rebound is redefined.•The eastern boundary of the Amurian Plate in Sea of Japan area is traced.
The 11 March 2011 Tohoku earthquake was the strongest event recorded in recent historic seismicity in Japan. Several researchers reported the deformation and possible mechanism as triggered by a mega thrust fault located offshore at the interface between the Pacific and the Okhotsk Plate. The studies to estimate the deformation in detail and the dynamics involved are still in progress. In this paper, coseismic GPS displacements associated with Tohoku earthquake are used to infer the amount of slip on the fault plane. Starting from the fault displacements configuration proposed by Caltech-JPL ARIA group and Geoazur CNRS, an optimization of these displacements is performed by developing a 3D finite element method (FEM) model, including the data of GPS-acoustic stations located offshore. The optimization is performed for different scenarios which include the presence of topography and bathymetry (DEM) as well as medium heterogeneities. By mean of the optimized displacement distribution for the most complete case (heterogeneous with DEM), a broad slip distribution, not narrowly centered east of hypocenter, is inferred. The resulting displacement map suggests that the beginning of the area of subsidence is not at east of MYGW GPS-acoustic station, as some researchers have suggested, and that the area of polar reversal of the vertical displacement is rather located at west of MYGW. The new fault slip distribution fits well for all the stations at ground and offshore and provides new information on the earthquake generation process and on the kinematics of Northern Japan area.
A procedure for determining the viscoelastic properties of apple flesh has been proposed based on compression tests and FEM optimization. Short-term simple compression tests and long-term relaxation ...tests were performed with cylindrical specimens of apple flesh to measure mechanical properties, and the viscoelastic behavior was predicted using FEM optimization models. Through short-term optimization, the elastic modulus and Poisson's ratio were determined by comparing two kernel functions based on 1) shear only and 2) shear and bulk terms. Long-term stress-relaxation behavior of the specimen was reasonably predicted by two FEM optimization steps within 3.8 % error. The FEM optimization algorithms developed in this research might be applied to determine the viscoelastic properties of bio-materials and also to predict mechanical behavior of these materials under various loading conditions.
An FEM algorithm was developed to determine the viscoelastic properties of soft tissues of agar/agar-gelatin gels based on the curve-averaged data from stress relaxation experiment of parallel plate ...compression and FEM optimization technique. This approach enabled more realistic and pertinent expression of the mechanical behavior of the gels than conventional methods, and allowed simultaneous and logical characterization of all viscoelastic parameters, based on geometry, relating to both Prony series and Maxwell model such as elastic modulus, Poisson's ratio, relative modulus, relaxation time, and dynamic viscosity, etc. Several assumptions were made in the FEM model such that the soft tissue materials were homogeneous in phase and isotropic, gravity effect was negligible, and the response was transient and controlled by displacement. To demonstrate the validity of the FEM model, the results of FEM optimization were compared with those of conventional method of nonlinear regression for agar/agar-gelatin gels, and also the predicted mechanical behavior of FEM on compressive creep as an interrelation with stress relaxation by the FEM model was compared with the experimental creep of 1% agar gel. The reliability of the FEM optimization method was confirmed by small stress deviation within 4.7% between experimental data and the FEM simulation using optimized parameters for stress-relaxation evaluation for agar/agar-gelatin gels and by strain deviation within 3.4% for creep prediction of 1% agar gel.
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