Efficient Simulation Strategy Research Articles

Equivalent spring model and efficient numerical strategy for simulating mechanical performance of seam-clip connections in aluminum alloy high-vertical standing seam metal cladding systems

The equivalent spring model has been validated as effective in simulating the mechanical performance of seam-clip connections in typical steel high-vertical standing seam metal cladding systems (SSMCSs). To enhance its applicability, this study further refines the equivalent spring model by developing thickness-related stiffness calibration models and an efficient numerical strategy for seam-clip connections in the aluminum alloy SSMCSs. Tensile tests are initially conducted to analyze the material properties of specimens with three commonly used thicknesses. Subsequently, the mechanical performance of the aluminum alloy seam-clip connections with different thicknesses is systematically studied, followed by the development of thickness-related stiffness calibration models. The tensile test results reveal notable nonlinearities and variability in the mechanical performance. To simulate this mechanical performance equivalently in the finite element (FE) model using data from tensile tests, an efficient numerical strategy is developed. This strategy involves methods for implementing simplified connections to establish the equivalent spring model and techniques for efficiently creating these simplified connections. It is found that both connectors and spring connections with calibrated parameters from tensile tests can effectively replicate the mechanical performance of seam-clip connections. To further validate the effectiveness of the equivalent spring model and the efficient numerical simulation strategy, a comparison of structural responses of the double-span sheet module (DSSM) obtained from tests and FE analysis is performed. The results reveal that all simulated structural responses on the DSSM with three common sheet widths align well with the corresponding experimental results. This highlights the feasibility and efficacy of the equivalent spring model and efficient numerical strategy in simulating the mechanical performance of seam-clip connections and delving deeper into the structural responses of the aluminum alloy high-vertical SSMCSs.

Hybrid multiscale computational approach for heat transfer in GaN semiconductors

Abstract With ongoing advancements in semiconductor technology, understanding thermal transport in semiconductor devices—where phonons are the primary charge carriers—is crucial. This involves a multiscale process in which phenomena at different scales are governed by distinct control equations, necessitating various numerical methods. In this context, this paper introduces a novel multiscale simulation method called the Second-Order Reconstruction Operator Finite Difference Lattice Boltzmann Method (ROsFDLBM). This method effectively combines the Lattice Boltzmann Method (LBM) with the Finite Difference Method (FDM). ROsFDLBM employs reconstruction operators to accurately map the relationship between distribution functions and macroscopic physical quantities, significantly reducing errors caused by the transmission of interface information. The efficacy of this coupling scheme has been confirmed through an interface-coupled thermal diffusion model. Comparative analyses have revealed that the relative error of ROsFDLBM does not exceed 1.2%, demonstrating its superior accuracy. Further simulations of GaN devices have confirmed that traditional macroscopic methods tend to underestimate the temperature in the heat source area at micro-nano scales, with discrepancies reaching up to 60.9 K. Overall, the ROsFDLBM aligns with current research findings and offers an accurate and efficient simulation strategy for addressing complex heat transfer problems.

Rapid Screening of Emergent Febuxostat Adulteration in Functional Foods Based on a Simulation-Inspired High-Quality Antibody.

Due to the potential health risks of adulterated febuxostat in uric-acid-lowering foods, it is urgent to develop rapid detection methods. However, there are no fast analytical techniques for febuxostat yet. Herein, an efficient hapten simulation strategy was proposed to successfully produce a highly sensitive and selective monoclonal antibody toward febuxostat. Based on such a robust recognition element, easy colorimetric and ultrasensitive fluorescent lateral flow immunochromatographic immunoassays were first established, which can detect febuxostat as low as 60 μg/kg by the naked eye or 1.01 μg/kg by a commercial test strip reader with acceptable stability. Furthermore, in the recovery test and blind sample analysis, consistent results between our methods and the authorized liquid chromatography-tandem mass spectrometry method suggested the high accuracy and practicality of this work. The present work not only proposes a rational hapten design idea but also provides favorable tools for the rapid screening of febuxostat in functional foods.

Efficient simulation strategy to design a safer motorcycle

This work presents models and simulations of a numerical strategy for a time and cost-efficient virtual product development of a novel passive safety restraint concept for motorcycles. It combines multiple individual development tasks in an aggregated procedure. The strategy consists of three successive virtual development stages with a continuously increasing level of detail and expected fidelity in multibody and finite element simulation environments. The results show what is possible with an entirely virtual concept study—based on the clever combination of multibody dynamics and nonlinear finite elements—that investigates the structural behavior and impact dynamics of the powered two-wheeler with the safety systems and the rider’s response. The simulations show a guided and controlled trajectory and deceleration of the motorcycle rider, resulting in fewer critical biomechanical loads on the rider compared to an impact with a conventional motorcycle. The numerical research strategy outlines a novel procedure in virtual motorcycle accident research with different levels of computational effort and model complexity aimed at a step-by-step validation of individual components in the future.

Exergo-ecological analysis and life cycle assessment of agro-wastes using a combined simulation approach based on Cape-Open to Cape-Open (COCO) and SimaPro free-software

Thermochemical processes to convert bio-wastes into valuable products and bioenergy have been extensively studied in the literature. Experimental and, to a lesser extent, rigorous simulation papers concerning these processes have been widely considered and discussed in the literature. Nonetheless, there is still a gap to fill in providing a fast and reliable simulation scheme. In this paper, an efficient simulation strategy, combining the free-software COCO simulator for the bio-waste slow pyrolysis coupled with commercial SimaPro code to carry out the Life Cycle Assessment (LCA), was applied. The pyrolysis product yields at 673, 773, and 873 K were well predicted using mass and energy balances and a proposed reaction scheme from the literature. Simulations were validated using experimental data previously reported. The highest yield was 53.7% for biochar (673 K – stalk of white grape), 32% for bio-oil (773 K - marc of red grape), and 56.3% for gas (873 K - marc of white grape). The results from LCA and cumulative exergy demand (CExD) were useful to detect and reduce environmental impacts in previous stages of the process.

Numerical modeling on friction and wear behaviors of all-metal progressive cavity pump

The wear of the all-metal progressive cavity pump (AMPCP) has become one of the main concerns from various field applications of oil production. This work systematically reveals the mechanisms of the wear and lubrication between the stator and the rotor components of the AMPCP when lifting fluids. An efficient simulation strategy is proposed to couple the two simultaneous processes, including the rotor's dynamic behavior and material loss due to wearing. On this basis, a three-dimensional finite element model based on the explicit dynamic method is established to capture the rotation process of the rotor considering the pressure load of the inner fluid. In addition, the frictional contact and wear behavior between stator and rotor is described as well. In this regard, the wear estimation model based on the Archard wear theory is developed to depict the material loss with a geometry update and local remeshing technique, the reliability of which is well verified against experimental results. Based on the statistical results of characteristic contact time (CCT) and characteristic wear band (CWB), the wear pattern is summarized into three distinctive bands denoted by CWB I, CWB II, and CWB III, which occurs at different stages during the operating cycles of AMPCP. In particular, the influence of operational parameters (e.g., rotation speed, clearance, and lubrication) on the wear behavior and its underlying mechanisms are quantitatively revealed and discussed. The results demonstrate that the lubrication effect could substantially reduce the wear degree to extend the service life of AMPCP.

New press deflection measuring methods for the creation of substitutive models for efficient die cambering

Cost and time for die tryout are significant within the car industry, and elastic deflections of dies and presses are most commonly not considered during the virtual die design and forming simulation phase. Because of this, active surfaces of stamping dies are only cambered based on previous experiences of tool types and presses. However, almost all stamping dies and presses are unique, and available experiences are not valid for new materials. Partners within the Eureka SMART Advanced Manufacturing research project CAMBER have developed advanced deflection measuring devices to quantify the elastic deformations of presses. Using these measurements, cambering methodologies can be utilized in sheet metal forming simulations. Important breakthroughs in recent years enabling the cambering methodology consists of efficient simulation strategies for full scale simulations with elastic dies and optimization techniques for creating substitutive press structures based on measurements. Furthermore, modern press deflection measurement methods are beneficial in applications such as Industry 4.0, predictive maintenance, product quality control, etc. through a more advanced understanding and live monitoring of the press system.

Three-dimensional modelling of shear keys in concrete gravity dams using an advanced grillage method

Contraction joint shear keys are resilient features of gravity dams that can be considered to increase the sliding safety factors or minimise seismic residual sliding displacements, allowing costly remedial actions to be avoided. This paper presents a novel, robust, and computationally efficient three-dimensional (3D) modelling and simulation strategy of gravity dams, using a series of adjacent cantilever beam elements to represent individual monoliths. These monoliths are interconnected in the longitudinal direction by 3D no-tension link elements representing the lumped shear key stiffness contributions at a particular elevation. The objective is to assess the shear key internal force demands, including the axial force, shear, and moment demands. Shear key demand-capacity ratios can then be assessed with related multi-axial failure envelopes. The 3D link element stiffness coefficients were derived from a series of 3D finite element (FE) solid models with a detailed representation of geometrical features of multiple shear keys. The results from the proposed method based on advanced grillage analysis show strong agreement with reference solutions from 3D FE solid models, demonstrating high accuracy and performance of the proposed method. The application of the proposed advanced grillage method to a dam model with two monoliths clearly shows the advantage of the proposed method, in comparison to the classical approach used in practise.

An efficient strategy for 3D numerical simulation of friction stir welding process of pure copper plates

Copper and its alloys have a wide spectrum of engineering applications such as heat exchangers, hot water tanks or nuclear pressure vessels. Most of these structures are obtained by welding. Unfortunately, the use of conventional arc welding process is affected by several factors such as the thermal conductivity of the alloy being welded, the shielding gas, the joint design, the welding position, and the surface condition and its cleanliness. Friction stir welding process could be an interesting alternative as it can be performed without melting the material, it involves a non-consumable tool, and provides good mechanical properties. To understand in depth both the physical and the thermal mechanisms involved in this process, numerical modelling is essential. The aim of this paper is to propose an efficient simulation strategy based on the coupled Eulerian Lagrangian finite element method. The mass scaling procedure, which is used to decrease the computation time will be presented, as well as its effect on the temperature field distribution and on the down force. This model will then be used for a parametric study in order to improve the friction welding process’s parameters.

Modeling Nonlinear Steady-State Induction Heating Processes

In this article, an efficient simulation strategy for a fully coupled nonlinear magnetic-thermal problem is presented. The solution-dependent magnetic subproblem is solved with a harmonic balancing scheme, with the main focus on the correct choice of the material model (magnetization curve). To further increase the computational efficiency, a non-conforming interface approach is used, based on the jump operators and penalty terms. This method drastically decreases the meshing time because different mesh sizes can be combined without taking care of element distortions in transition layers between fine and coarse parts of the mesh.

Coupled Thermo-Mechanical Analysis of 3D ICs Based on an Equivalent Modeling Methodology With Sub-Modeling

The coupled thermo-mechanical field analysis of three-dimensional (3D) stacked integrated circuits (ICs) is evaluated by an efficient and accurate simulation strategy that combines equivalent homogenization modeling methodology and sub-modeling technique. The thermal field is first investigated using the proposed approach, and based on which the structural field is also examined through the calculation of warpage. The utilization of sub-modeling method reveals the local temperature and warpage distributions, which is lost or ignored by the conventional homogenization method. To validate the proposed method, the simulation results of a five-layer stacked integrated circuits are compared against true 3D results of the detailed model, where the maximum deviation for temperature and warpage is as low as 1.62% and 4.89%, respectively, which are greatly improved compared to 8.23% and 7.83% using traditional homogenization method. In addition, the total computation time is reduced by 76.7% in contrast to true 3D finite element analysis (FEA) simulation. Furthermore, the impacts of through-silicon-via (TSV) geometries, underfill and μ -bump parameters on the temperature and warpage distributions are also studied to guide the design of 3D ICs with high performance and reliability.

An adaptive MOR method for vibro-acoustic analysis of dynamic systems with viscoelastic damping

Viscoelastic materials have the capability of dissipating vibrational energy which makes them very effective in the passive control of structural vibration and noise radiation. Efficient modeling-and simulation strategies for vibro-acoustic systems with these frequency-dependent damping materials are necessary. One way of doing that is to utilize the finite element (FE) method supported by a damping model that describes the frequency-dependency of the complex elastic modulus. However, in many applications, very large-scale FE models are required to obtain reliable predictions, which makes full-order system evaluation often intractable. Model order reduction (MOR), however, cannot be directly applied to models including viscoelastic materials due to the frequency-dependent property which exactly makes that the equations of motion are not of a standard second-order form as that for regular FE models. In this paper, a transformation technique based on Taylor’s theorem is introduced to treat the non-standard form of the equations of motion. After transforming the problem into a second-order system equation with an associated remainder term, an adaptive MOR procedure is applied to reduce the computational complexity of the vibro-acoustic systems. A numerical example is provided to demonstrate the simplicity and efficiency of the proposed approach.

A modal coordinate catenary model for the real-time simulation of the pantograph-catenary dynamic interaction

The computational cost required to simulate the pantograph-catenary dynamic interaction can be a limiting factor in certain applications. Specifically, for Hardware-in-the-Loop (HIL) simulations, real-time capabilities of the software are imperative. In this paper a combination of a modal coordinate approach with an offline/online strategy to build a very efficient simulation strategy is proposed. This novel approach preserves the accuracy of the results, compared with those obtained by classical finite element strategies. Furthermore, a procedure to define and validate a criterion for a priori truncation of the modal basis and an analysis of the effect of explicit treatment of the interaction force are also presented. The results show that the method proposed could be used to perform pantograph HIL tests.

Practical rare event sampling for extreme mesoscale weather

Extreme mesoscale weather, including tropical cyclones, squall lines, and floods, can be enormously damaging and yet challenging to simulate; hence, there is a pressing need for more efficient simulation strategies. Here, we present a new rare event sampling algorithm called quantile diffusion Monte Carlo (quantile DMC). Quantile DMC is a simple-to-use algorithm that can sample extreme tail behavior for a wide class of processes. We demonstrate the advantages of quantile DMC compared to other sampling methods and discuss practical aspects of implementing quantile DMC. To test the feasibility of quantile DMC for extreme mesoscale weather, we sample extremely intense realizations of two historical tropical cyclones, 2010 Hurricane Earl and 2015 Hurricane Joaquin. Our results demonstrate quantile DMC’s potential to provide low-variance extreme weather statistics while highlighting the work that is necessary for quantile DMC to attain greater efficiency in future applications.

Multiscale formulation for coupled flow-heat equations arising from single-phase flow in fractured geothermal reservoirs

Efficient heat exploitation strategies from geothermal systems demand for accurate and efficient simulation of coupled flow-heat equations on large-scale heterogeneous fractured formations. While the accuracy depends on honouring high-resolution discrete fractures and rock heterogeneities, specially avoiding excessive upscaled quantities, the efficiency can be maintained if scalable model-reduction computational frameworks are developed. Addressing both aspects, this work presents a multiscale formulation for geothermal reservoirs. To this end, the nonlinear time-dependent (transient) multiscale coarse-scale system is obtained, for both pressure and temperature unknowns, based on elliptic locally solved basis functions. These basis functions account for fine-scale heterogeneity and discrete fractures, leading to accurate and efficient simulation strategies. The flow-heat coupling is treated in a sequential implicit loop, where in each stage, the multiscale stage is complemented by an ILU(0) smoother stage to guarantee convergence to any desired accuracy. Numerical results are presented in 2D to systematically analyze the multiscale approximate solutions compared with the fine scale ones for many challenging cases, including the outcrop-based geological fractured field. These results show that the developed multiscale formulation casts a promising framework for the real-field enhanced geothermal formations.

Efficient simulation strategy for PCM-based cold-energy storage systems

This paper proposes a computationally efficient simulation strategy for cold thermal energy storage (TES) systems based on phase change material (PCM). Taking as a starting point the recent design of a TES system based on PCM, designed to complement a vapour-compression refrigeration plant, the new highly efficient modelling strategy is described and its performance is compared against the pre-existing one. The need for a new computationally efficient approach comes from the fact that, in the near future, such a TES model is intended to be used in combination with the model of the own mother refrigeration plant, in order to address efficient, long-term energy management strategies, where computation time will become a major issue. Comparative simulations show that the proposed computationally efficient strategy reduces the simulation time to a small fraction of the original figure (from around 1/30th till around 1/120th, depending on the particular choice of the main sampling interval), at the expense of affordable inaccuracy in terms of the PCM charge ratio.

Divertor design through adjoint approaches and efficient code simulation strategies

Divertor power exhaust is one of the main issues to be addressed on the way to reliable fusion power plants. It is generally accepted that at least partially detached operation is essential to mitigate the heat and particle loads to the divertor target plates. These highly dissipative regimes pose serious challenges to the plasma edge codes used for the design of these components, leading to exacerbated runtimes and convergence problems due to the presence of statistical noise in the code system. Moreover, the large number of design variables precludes investigating a wide range of designs and operating points. Building on a framework of code speed‐up based on the minimization of numerical errors in coupled finite‐volume Monte Carlo codes, we develop an efficient discrete adjoint technique for the automated solution of divertor design problems. We are able to compute the sensitivity information with very low variance, despite the statistical noise. By integrating the sensitivity analysis into a one‐shot optimization algorithm, robust convergence of the optimization problem is achieved at a cost independent of the number of design variables. The results are encouraging for the development of adjoint‐based optimization techniques for plasma edge codes such as SOLPS‐ITER.

Developing a robust proxy model of CO2 injection: Coupling Box–Behnken design and a connectionist method

The CO2 based enhanced oil recovery methods (EORs) in the petroleum industry are considered as one of the efficient technologies for further production where the natural driving forces become weak. To determine which EOR method is more appropriate for a targeted reservoir, there is a need to develop a reliable and fast tool to predict the performance of the EOR methods due to assumptions and central processing time (CPU) time of reservoir simulations. We develop a promising approach for predicting the ultimate oil recovery factor of the miscible CO2 injection processes. To attain this goal, the least square support vector machine is used to build the proxy model. The Box-Behnken design as a branch of response surface methods is employed to design simulation runs for miscible CO2 injection processes, and the leverage method is applied to validate the proxy model in terms of statistical perspective. An artificial heterogeneous reservoir is used to perform compositional reservoir simulations. Five operational parameters of the miscible CO2 injection process are considered, including bottom-hole flowing pressure (BHP) of injection well (psi), CO2 injection rate (MMSCF/D), injected CO2 concentration (mole fraction), bottom-hole flowing pressure (BHP) of production well (psi), and oil production rate (STB/D). The developed proxy model can be employed to forecast the ultimate oil recovery factor of the miscible CO2 injection operations at the different rock, fluids, and process conditions. The proposed method appears to be an efficient simulation strategy that offers guidelines and screening criteria for the application of the miscible CO2 injection.

Prediction of Aperture Efficiency Ripple in Clear Aperture Offset Gregorian Antennas

Electrically small clear aperture dual offset reflector systems often exhibit a directivity ripple over frequency due to the interference of the diffracted field from the sub-reflector with the main beam field. This paper investigates the cause of the ripple, and presents a technique to predict the expected system directivity, including the ripple, using the feed radiation pattern augmented by an efficient simulation strategy in a clear aperture offset Gregorian system. The method allows for accurate prediction of the directivity ripple using a severely under-sampled set of simulation results. Predicted results are compared to several simulations, and agreement to better than 0.5 % is found for the majority of configurations using both analytical and full wave simulated feed patterns.

Towards an efficient multiscale modeling of low-dimensional reactive systems: Study of numerical closure procedures

We study a numerical closure approach for systems of chemically reacting systems [corrected] on lattices with low-dimensional support, for which a mean-field approximation is insufficiently accurate because of lateral interaction on the lattice. We introduce a hierarchy of macroscopic state variables, taking particle clusters into account, whose time evolution is obtained via microscopic (kinetic Monte Carlo) simulation. The macroscopic state variables are chosen such that they can be [corrected] straightforwardly conserved during reconstruction of a microscopic configuration (the so-called lifting step). We present and compare the effects of different alternatives to initialize the remaining degrees of freedom. We illustrate the strong interplay between the number of macroscopic state variables and the specifics of the lifting and that, for a given lifting operator, accuracy of the macroscopic dynamics does not necessarily improve monotonically when adding macroscopic state variables.