Proposed Design Procedure Research Articles

Component design procedure for LCC‐S wireless power transfer systems based on genetic algorithms and sensitivity analysis

AbstractThis paper introduces a novel approach for designing a Wireless Power Transfer (WPT) system with LCC‐S compensation. Since WPT systems operate under resonant conditions, even small deviations of the components from the nominal values can result in a significant reduction of the power transferred to the load, and in an increment of the circulating currents, reducing the system efficiency. The design techniques available today in the literature provide a unique combination of passive components capable of transferring a certain power to the load. This is a limitation, because, in practice, there are several combinations that allow reaching the desired output power, but they are usually neglected because they are extremely difficult to compute analytically. For this reason, in this paper, the authors present an innovative design procedure that enables, through a Genetic Algorithm, the identification of multiple feasible combinations of the LCC‐S components capable of achieving the desired output power. Moreover, the authors evaluate the effects of the component tolerances on the output power to determine which combinations are more robust to component variations. This task is performed by calculating the probability that a particular combination yields the desired output power, once the tolerances have been considered, following a Monte Carlo approach. This information is utilized to decide whether it is possible to reduce the component quality (worsening the tolerance) without affecting the performance. Finally, an optimal solution granting both low‐cost and robustness against component tolerances can be individuated. The proposed design procedure is applied to a case study and validated experimentally.

Interaction-performance-driven design of negative-stiffness friction pendulum systems for aboveground structure–connected underground structure–soil system with ground motion effects

Within the transit-oriented development framework, aboveground structure–connected underground structures (ASUS) have been widely constructed in urban areas; however, abrupt stiffness changes and complex soil–structure interactions could cause structural damage or business disruption after earthquakes. In this study, to address these challenges, a novel approach is proposed that employs negative stiffness, damping elements, and friction pendulum bearings to enhance the overall performance of ASUS. An interaction-performance-driven design procedure and parameter selection methodology are developed to simultaneously upgrade multiple performance aspects of ASUS. A mechanical model of the negative stiffness amplification system-enabled friction pendulum system (NSAS-FPS) is constructed. The theoretical basis of the equivalent negative stiffness and enhanced energy dissipation effects is elucidated, and a finite element model of the NSAS-FPS-incorporated soil–ASUS interaction system is established. Extensive parametric, robustness, and correlation analyses against short/long-period ground motions are conducted to provide a comprehensive performance assessment framework. Then, an interaction-performance-driven design principle aimed at multiperformance upgrading of aboveground and underground structures is developed with proposed parameter selections and applied in a case study. These results indicate a significant improvement in vibration control for both aboveground and underground structures when utilizing NSAS-FPS compared to utilizing conventional FPSs with the same design. By following the proposed design procedure and parameters, the NSAS-FPS demonstrates enhanced efficiency in isolating energy dissipation and robustness in seismic isolation, as well as resistance against overturning, irrespective of variations in structural masses and functionalities. While the advantages of the NSAS-FPS include its ability to mitigate the effects of stochastic earthquakes, the extent of the performance improvement may decrease during long-period earthquakes. Therefore, the velocity characteristics of seismic excitations need to be carefully incorporated into the NSAS-FPS design, particularly when targeting specific demands for the isolation-layer performance within ASUS.

The conceptual design and process intensification of the separation of ternary azeotropic mixture with heterogeneous characteristic

A substantial amount of ternary azeotropic mixtures with heterogeneous properties are generated in the production processes of the pharmaceutical and fine chemicals industries. While the presence of heterogeneous features complicates the thermodynamic behavior of such mixtures, it also creates opportunities for separations using heterogeneous distillation. Thus, this study focuses on the conceptual design and process intensification for the separation of heterogeneous ternary azeotrope mixtures integrating decanter, distillation, and heat pump technology. Based on the characteristics of a mixture with a liquid-liquid partial miscibility region, the design procedure including conceptual design, multi-objective optimization, and heat pump-assisted intensification has been proposed. The separation of acetonitrile-cyclohexane-toluene is used to illustrate the capability of the proposed design procedure. The results demonstrated that the heat pump-assisted process including one decanter, one distillation column, and two stripper columns provides the best separation process, excelling in economic, environmental, and thermodynamic performance, whose TAC is 76.15% lower than the conventional heterogeneous distillation.

A new hybrid steel–timber rocking seismic force resisting system equipped with U-shaped fuse connections

This paper introduces a new low-damage hybrid steel–timber rocking braced frame with self-centring capability and proposes a design methodology in the framework of Canadian design standards. This system consists of a gravity load-resisting timber frame and a steel concentrically braced frame acting as the lateral load-resisting system that is connected using U-shaped steel fuses. The self-centring capability is achieved by post-tensioning strands and rocking bases within the lateral load-resisting system. The system, along with its components, is first introduced. The proposed design method and system performance objectives are then presented. The seismic performance of the system and the proposed design procedure are validated through numerical analyses considering the interaction between the lateral and gravity load-resisting systems. The results of dynamic analyses confirm the enhanced seismic performance of the proposed hybrid system with almost no residual deformations after the earthquake. Moreover, the proposed design guidelines can accurately predict the system’s seismic response and demands imposed on the members.

Core losses analysis of the LCL filter inductor for SiC-based inverter

The ability of SiC devices to switch at high speed allows increasing significantly the power density in both converters and passive components, reducing their required size. To mitigate harmonic injection form inverters into the grid, in order to comply with power quality standards, an accurate filter design is required. Given its excellent performance, an LCL filter is the configuration most suitable in grid-connected power converters. Several parameters must be considered when designing an effective LCL filter, and the inverter-side inductor assumes a special importance because of its relevance to suppress high frequency harmonic content at the inverter side. One of the most relevant issues to be considered in the process of designing the LCL filter is the evaluation of core losses in the inverter-side inductor, which will determine the final temperature of the inductor. This paper analyses the core losses of the inverter-side inductor of an LCL filter. The proposed method is based on the computation of the current harmonics generated by the inverter and on Steinmetz’s empirical equation. As a result, core losses calculated taking into account several carrier and sideband harmonics show good agreement with the experimental values. When current harmonics are estimated by simulation, as it is done in the proposed design procedure, results are less accurate, but precise enough for a design procedure.

Numerical studies on the flow characteristic of the marine two-stroke engine integrated with the high-pressure exhaust gas recirculation system

The high-pressure exhaust gas recirculation (HP-EGR) has been well-proven for marine engines complying with the IMO Tier Ⅲ NOx regulation. Considering different turbocharged scavenging schemes and emission control modes, intake and exhaust gas management is critical to the HP-EGR design. However, few theoretical studies on it were reported. This paper aims at providing a case study on the flow characteristic of the turbocharged HP-EGR system. With the proposed topology structure of the typical HP-EGR layout, numerical studies on the turbocharged scavenging and EGR design were conducted based on the 6EX340 two-stroke engine. The result showed that the flow characteristic of the turbocharged two-stroke engine can be graphically depicted by simplifying the cylinder and turbine as multi-nozzle in series. According to the nozzle flow equation of uniflow scavenging, there exists an optimum turbine flow area to maximize the scavenging mass flow. Effects of EGR, cylinder bypass, and exhaust gas bypass on the flow characteristic of the two-stroke engine depend on the turbocharger matching. The out-cylinder scavenging and in-cylinder combustion should be optimized interactively to fully explore the fuel economy and NOx trade-off. Finally, the proposed design procedure can provide good guidance for the design and control of the HP-EGR system.

A Method for Preliminary Design of Variable Geometry Vaned Diffuser for Centrifugal Compressor

Abstract Centrifugal compressors require a wide operating range as well as high efficiency. Typical active control forms to enhance the operating range are suction throttling with a valve in a suction line, discharge throttling with a ring installed in a vaneless diffuser, variable inlet guide vanes, and variable geometry vaned diffuser (VVD). This study focuses on the design of a VVD whose vane rotates around a pivot to adjust its opening and proposes a method to estimate the main parameters of the VVD at the preliminary design stage. The design method here is based on matching the diffuser vane inlet angles with the flow angles at the diffuser inlet. If the designed VVD can maintain low incidence at the diffuser vane leading edge over the whole movable range of the vane is evaluated. A graph, which indicates the relation between the diffuser vane inlet angles and the flow angles at the diffuser inlet at diffuser choking and diffuser stalling, makes the evaluation easy. The proposed procedures were applied to select the number of vanes of the VVD for a turbocharger compressor. Tests for the validation of the design procedures were conducted by using fixed vaned diffusers that simulated the VVDs installed on the turbocharger with an 85 mm-diameter impeller. The results showed the effectiveness of the proposed design procedures. This paper first presents examples of applications of the typical active methods extending centrifugal compressors’ operating range for real machines and then discusses the design of VVD.

Numerical and Analytical Determination of Rockburst Characteristics: Case Study from Polish Deep Copper Mine

A simplified analytical method useful for ductile ground support design in underground mine workings is presented. This approach allows for maintaining the stability of sidewalls in rectangular openings extracted in competent and homogeneous rocks, especially in high-pressure conditions, favoring rockburst event occurrence. The proposed design procedure involves the typical assumptions governing the limit equilibrium method (LEM) with respect to a triangular rock block expelled from a sidewall of a long mine excavation subjected to normal stresses of the values determined based on the Maugis’s analytical solution concerned with stress distribution around the elliptical opening extracted within the homogeneous infinite elastic space. This stage of the local assessment of rock susceptibility to ejection from the walls of the excavation allowed for determining the geometry of the block whose ejection is most likely in a given geological and mining situation. Having extensive information about the geometry of the excavations and the properties of the surrounding rocks, it was possible to make an exemplary map of the risk from rockburst hazard, developed as the 2D contours of safety indexes’ values, for special-purpose excavations such as heavy machinery chambers, main excavations, etc. in conditions of selected mining panel of the deep copper mine at Legnica-Głogów Copper Basin, Poland. Another important element of the obtained results is the calculated values of the horizontal forces potentially pushing out the predetermined rock blocks. These forces are the surplus over the potential of frictional resistance and cohesion on the surfaces of previously identified discontinuities or on new cracks appearing as a result of overloading of the sidewalls. Finally, the presented algorithm allows us to perform quantitative tracking of rockburst phenomena as a function of time by determination of acceleration, velocity, and displacement of expelled rocks. Such information may be useful at the stage of designing the support for underground workings.

Water network integration for industrial park based on numerical indicators

This paper presents a numerical approach for water network integration of industrial park. A new numerical indicator General Treatment Potential (GTP) is proposed to reflect the general potential of the source streams to be treated by the treatment unit. To design the public distributed treatment system, the source streams are arranged in descending order of their GTP values, and treated in turn. To design the reused network in each plant, the treated streams are added into the plant as source streams, and reused by the demand streams. The final integrated water network can be obtained in several iterations. Three examples with two cases, network retrofitting and network design, are investigated to show the proposed approach. The results show that the proposed design procedure can reduce the freshwater consumption, cut down the annualized cost, or simplify the structure of the water network in industrial park.

A Novel Synthesis of Quasi-Chebyshev Ultra-Wideband Bandpass Filter Using Nth Order Stub Loaded Coupled-Line Resonator.

This paper presents a novel synthesis of a quasi-Chebyshev Nth order stub-loaded coupled-line ultra-wideband bandpass filter. A unit element of a proposed filter topology consists of two short-circuited stubs loaded at the edges of coupled lines. A distributed equivalent circuit model of a proposed topology is extracted and used to acquire a generalized filtering function. The extracted filtering function is of rational form. The denominator of the filtering function causes a mismatch with Chebyshev type-I polynomials. For conventional narrowband filters, the denominator term can be neglected because of the close vicinity of band-edge frequencies; however, for the ultra-wideband filter response, the factor in the denominator cannot be neglected and hence requires a new mathematical procedure to compensate for the effect of the frequency-dependent term in the denominator. The electrical parameters are calculated using the proposed synthesis and used to design an ideal filter topology on ADS. To validate the proposed design procedure, fabrication is performed on a high-frequency substrate. The proposed filter is miniaturized in size and has good out-of-band performance. The simulated and measured results provide good agreement.

Enhancing deep reinforcement learning with integral action to control tokamak safety factor

Recent advances in the use of Artificial Intelligence to control complex systems make it suitable for profile plasma control. In this work, we propose an algorithm based on Deep Reinforcement Learning to control the safety factor profile with a feedback design. For this purpose, we first derive a device-specific control-oriented model with fast simulation time. Then, in order to enhance robustness with respect to external disturbances and model errors, we include an error time integrator into the controller. A cascade of the kinetic and magnetic models with the error time integrator is used in the learning procedure of the feedback controller. Finally, to illustrate the efficiency of the proposed design procedure, the obtained controller is tested in a reference plasma simulator, the Raptor simulator.

Structural design using reclaimed wood – A case study and proposed design procedure

Applying circular economy principles through the structural reuse of reclaimed wood in new construction can reduce the climate impact of the construction industry. The ability to reuse reclaimed wood products in new structural design is limited by the modern wood industry and design process. This paper describes the implementation of new processes that allow designers to account for variability in the dimension and mechanical properties of reclaimed wood in a case study design-build project on the Cornell University campus in 2022. Dimension variability was approached with a parametric design workflow. The assignment of mechanical property design values to reclaimed wood was approached through species identification, functions that related mechanical properties to specific gravity, and static bending tests. The process based on species identification was sufficient but led to underutilization of structural members. A design method which uses adjusted functions that relate mechanical properties to specific gravity is proposed.

Peeling-Versus-Shear Failures in Prematurely Collapsing RC Beams Strengthened in Flexure

Failure modes of flexurally strengthened reinforced concrete (RC) beams can be broadly classified into full-bond response and partial-bond response. Among these, peeling (premature failure) and shear-block failure are closely related and cause catastrophic collapse. Provisions in current design standards are largely generalized (too simplified or too complex), and tend to ignore some key parameters. In particular, design standards have not clearly characterized the effect of shear on the peeling. In this work, experiments and numerical studies have been conducted to investigate the shear-peeling failure and differentiate it from other failure modes. The results have been used to extend the existing design recommendations. The proposed design procedure and the finite element (FE) models are validated, and the outcome is compared with the literature. The comparison and the use of the Chi-squared test showed that the proposed design formulations are more appropriate for calculating the moment capacity and predicting the sequence of failure modes of plated RC beams.

A Method for Improving the Caching Strategy for Computing Systems with Shared Memory

This paper considers the problem of increasing the software efficiency in terms of reducing the costs of their development and operation in the process of solving production and research tasks. We have analysed the existing approaches to solving this problem by example of parameterized algorithms for implementing mVm (matrix—vector multiplication) and MMM (matrix—matrix multiplication)) BLAS (Basic Linear Algebra Subroutines) operations. To achieve the goal of increasing the software efficiency, we proposed a new design method, designed to improve data caching algorithms in the software development for computing systems with a hierarchical memory structure. Using the proposed design procedure, we developed an analytical approach to evaluating the software effectiveness from the point of view of using a memory subsystem with a hierarchical structure is implemented. We applied the proposed method to the two-sided Householder transformation for the task of reducing the general form matrix to the Hessenberg form. Then we presented new algorithms for solving the problem, which are optimized variants of the Householder classical transformation: Row-Oriented Householder and Single-Pass Householder. The use of these algorithms can significantly reduce the software execution time. Computational experiments were carried out on a parallel computing system with shared memory, which is one of the nodes of the computing cluster of the Volgograd State Technical University. We made a comparison of the software execution time that reduce general-form matrices to Hessenberg form, written using the proposed algorithms and using the LAPACKE_dgehrd() function of the Intel MKL library. The conclusions made in the work are confirmed by the results of the conducted computational experiments.

Design, Modelling and Optimization of a High Power Density Axial Flux SRM with Reduced Torque Ripple for Electric Vehicles

Switched reluctance machines (SRMs) are potential candidates for use in the propulsion systems of electric vehicles. However, they suffer from low power density and high torque ripple. In this paper, a segmented rotor double-sided axial flux SRM (DSAFSRM) is chosen for detailed analysis. A hybrid design algorithm is proposed to take the effects of iron non-linearity into account. The proposed design procedure benefits from simplicity and high accuracy at the same time. A two-step optimization procedure is presented which minimizes the torque ripple of the DSAFSRM without jeopardizing its efficiency. The torque ripple is reduced from 120% to 35% after optimization. In the two-step optimization procedure, both geometrical and switching related parameters are investigated. Moreover, a double-sided radial flux SRM is designed and compared with the proposed DSAFSRM in terms of torque ripple, average torque, efficiency and power density. The results indicate superior performance of the optimized DSAFSRM, especially in terms of average torque, which is 26% higher than the torque produced by the double-sided radial flux SRM.

Robust design procedure for RC plates and shell structures using developed advanced sandwich model

In recent years, a notable increase in the number of complex concrete roofs has been observed. Simultaneously, the design codes lack design approaches for such structures in which the elements are subjected to combined forces (membrane and transverse) and moments (flexure and torsion). The finite element-based design (FEBD) has been provided for these structural elements; however, it is not widely adopted for the design. Hence, there is an urgent need to fill this gap. Therefore, an automatic FEBD procedure is developed in this study based on the equilibrium consideration, named the developed advanced sandwich model (DASM). The element cracking inspection was performed according to the multi-axial compression state of concrete. Subsequently, the DASM was developed to account for the effect of transverse shear forces. The proposed design algorithm was developed using a Python script linked with ABAQUS software to perform an automatic design for all elements and to be presented as a practical design tool. Additionally, the damage-based analysis was performed as an assessment tool to demonstrate the efficiency of the proposed design procedure. This study illustrated that using the DASM reduced the steel reinforcement by up to 40% and increased the ductility by 10–15%. Also, it is observed that the ultimate capacity of the considered examples, including the solid plate and flat plate, slightly decreased by 4.1% and 1.8% (less than 5%), respectively, which hardly affects the overall response of the designed structure. Indeed, these results demonstrate the efficiency of the developed procedure. In summary, the results of this study indicate that the proposed design framework (DASM) presents a highly accurate, relatively simple, and robust procedure for designing plate and shell structures with complex geometry, where the design process can be completed on a standard personal computer in a few seconds.

Voltage and active power local PI control of distributed energy resources based on the effective transfer function method

This paper presents the design of local PI regulators to control voltage and active power of the Distributed Energy Resources (DERs) in grid-connected Active Distribution Networks (ADNs). The design is developed based on the proposed Multiple-Input Multiple-Output (MIMO) model of ADN. Firstly, the Relative Gain Array (RGA) matrix is used to address the problem of input–output pairing and to show that the voltage control loops are coupled whereas the active power control loops are decoupled. Subsequently the method of the Effective Open-Loop Transfer Function (EOTF) is used to decompose the multi-loop voltage control system into a set of equivalent Single-Input Single-Output (SISO) loops. Then, each PI regulator is independently designed to fulfill some control objectives dictated by the designer. The proposed design procedure is simple and straightforward. The fixed-parameters PI regulators facilitate the integration of DERs into traditional distribution networks which are usually operated without or with limited communication infrastructure. The simulation results presented for various scenarios of two different ADN confirm that performance objectives and regulation at the desired set-points are achieved in a robust sense.

A Novel Hybrid Self-Centering Piston-Based Bracing Fitted with SMA Bars and Friction Springs: Analytical Study and Seismic Simulation

Self-centering piston-based braced frames (SC-PBBFs) are such structural assemblies that can withstand a severe earthquake through passive control. The self-centering motion of the bracing system curtails the seismic permanent damage of a building, thereby considerably mitigating postearthquake repair costs and downtime. This paper proposes a novel hybrid self-centering piston-based bracing (SC-PBB) equipped with friction springs (FS) and superelastic shape-memory alloy (SMA) bars. Analytical formulas are presented for rapid analysis and preliminary seismic design of the SC-PBBFs fitted with SC-PBBs. The general mechanics of the proposed archetypes confirms their symmetric self-centering behavior. To validate the proposed design procedure, a set of SC-PBBFs fitted with tension-only SMA bars and precompressed FS is examined under far-field ground motions. Effects of prestressing of components and earthquake types (crustal, subcrustal, and subduction) are quantified and compared with the responses of buckling-restrained braced frames (BRBFs). The analysis outcomes revealed the effectiveness of the proposed hybrid SC-PBBF subjected to design-level earthquakes.

Seismic collapse assessment of hybrid self-centering piston-based braced frames equipped with SMA bars and friction springs

Hybrid Self-centering Piston-Based Bracing (SC-PBB) is a cutting-edge, resilient earthquake-resistant element that comprises friction springs (FSs) and super-elastic shape memory alloy (SMA) bars. This innovative bracing component is specifically devised to attain a full self-centering response under a design-level earthquake, effectively mitigating the need for post-earthquake repairs and downtime. Nevertheless, concerns surrounding the potential collapse of Self-centering Piston Based Braced Frames (SC-PBBFs) during severe seismic motion have highlighted the necessity for a comprehensive collapse assessment. This paper evaluates the seismic collapse of SC-PBBFs by utilizing the FEMA P695 methodology. A set of buildings ranging from low- to high-rise archetypes is designed with a proposed response modification coefficient of R = 8. Incremental dynamic analyses (IDA) are conducted under 44 far-field ground motions to evaluate Adjusted Collapse Margin Ratios (ACMRs). Additionally, the collapse risk of the archetypes is measured under the influence of system-level uncertainty. The outcomes indicate that the proposed design procedure ensures an adequate margin of safety against collapse for SC-PBBFs.

Structural fuse performance and earthquake-resilient performance of beam-column joints with replaceable T-stub

In order to ensure that steel frame systems have excellent structural fuse performance and earthquake-resilient performance on the basis of good seismic performance, a novel steel beam-column joint with replaceable T-stub connection components (SBCJ-RTCCs) was proposed. The pseudo-static cyclic tests of original and replaced specimens were carried out. As an extension of the experimental tests, numerical parametric analyses were performed to determine an optimal range of resistance capacity ratio to make a balance between the seismic performance, structural fuse performance and earthquake-resilient performance. The analysis results demonstrated that despite seismic performance of specimen with a small resistance capacity ratio is relatively weak, the structural fuse performance and earthquake-resilient performance performed well. With the increase of resistance capacity ratio, the seismic performance consisting of initial stiffness and bearing capacity gradually improved. However, the plasticity and damage would be shifted from RTCCs to non-fuse components, which adversely affected the structural fuse performance, despite the earthquake-resilient performance of specimen was still good. In terms of comprehensive consideration of seismic performance, structural fuse performance and earthquake-resilient performance, the resistance capacity ratio was suggested as 0.53–0.63. Moreover, a design procedure of SBCJ-RTCCs was proposed, and its rationality was validated by a design example RT-D. The result indicates that by adopting the proposed design procedure, the RT-D exhibited stable hysteretic behavior without experiencing strength degradation. The RTCCs can play the role of structural fuses by dissipating more than 90% of the input energy, which effectively protect the non-fuse components from damage.