Common Design Methods Research Articles

Assessment of a body force modeling approach to examine the aerodynamics of high bypass ratio fan stages

The primary focus of modern civil jet engine intake design is to enhance propulsive efficiency through an increase in the bypass ratio of the turbofan engine, which requires an enlargement in fan diameter. However, this enlargement results in increased weight and drag due to the need for a larger nacelle to surround the fan. To mitigate these issues, efforts are being made to shorten the axial length of the aircraft engine intakes. Nonetheless, this reduction leads to more vulnerable fan aerodynamics since the diffusion within the intake must occur over a shorter distance, causing a higher possibility of flow separation. Common intake design methods employ throughflow nacelle models that do not consider the aerodynamic effects of the fan, including blockage, mass flow redistribution, and suction. The utilization of a full annulus domain numerical setup, which is necessary to capture inlet distortions, demands excessive computational resources particularly during the design phase. As a result, reduced order models, such as the body force model, can be utilized to simulate fan intake aerodynamics. This paper will assess the body force model and its abilities by comparing conventional bladed single passage simulations with the body force approach.

Power Boundary Controlled Single-Stage LLC Power Factor Correction Converter and Its Optimal Parameter Design

The time-domain analysis on single-stage LLC power factor correction (PFC) converter is performed in this paper, which reveals that PON mode may occur around the peak point of instantaneous input power and cause instability issue. In order avoid PON mode, the power boundary between PO and PON mode is calculated. For the common design methods of LLC PFC converter with average mode control strategy, the power boundary requires to be higher than the instantaneous input power at its worst point. However, higher power boundary brings higher RMS value of resonant current, and causes higher reactive power loss. Therefore, it is a wasteful designing methodology, as the other points of instantaneous input power don't need such high power boundary. In order to improve the efficiency, a power boundary control strategy is proposed in this paper. By controlling the input current to make the instantaneous input power follow the power boundary, PON mode is eliminated. Consequently, the required power boundary is overall reduced, and the minimal RMS current of resonant tank can be achieved. Furthermore, the optimal parameter design is also presented. A 90∼240VAC input and 250W/48V output experimental prototype has been built to verify the analysis results.

Research Progress of Selective Laser Melting Forming Medical Implants

Abstract:: Selective laser melting technology has the advantages of rapid manufacture, high precision, and the ability to produce fine structures. Medical implants made using selective laser melting technology have high precision and excellent mechanical properties that meet the needs of patients and make medical implants more promising in the medical field. This paper reviews the progress of research on selective laser melting of medical implants. This paper draws on numerous journals and patents. This paper firstly reviews the classification of medical implants, mainly including hip implants, knee implants, maxillo-craniofacial implants and spinal implants. Secondly, the common porous structure design methods, the effect of porous structure on the mechanical properties of the implant, and the effect of pore structure on the growth properties of porous titanium alloy bone are summarised. Finally, the process of manufacturing titanium alloy implants by selective laser melting technology is described. Medical implants made by selective laser melting have excellent properties and are widely used in the medical field. Compared to traditional mechanical processing methods, selective laser melting technology can better preserve the properties of the raw material, while providing higher precision and faster preparation. However, selective laser melting has a number of drawbacks, including differences in material microstructure, reduced strength and plasticity, inadequate surface treatment, and enhanced safety and reliability. Further scientific research and technological innovation are needed to solve these problems. In the future, as technology continues to innovate and develop, SLM technology will become more mature, resulting in implants that are more natural, suitable for the body and long-lasting. At the same time, as implants are personalised, there will be a huge market demand and development opportunities. In addition, the continuous improvement of regulatory policies is expected to further promote the market development and application of medical implants.

Design method of frequency similarity relation for shaking table model test

It is very important to determine the dynamic similarity relation in the shaking table model test. The accurate dynamic similarity relation can make the model reflect the dynamic characteristics of the prototype to the greatest extent. This paper describes the principle of similarity design for shaking table model test and reviews the related literature. According to the different research objects and purposes, four common similarity design methods including separation similarity method, artificial mass method, less artificial mass method and ignoring gravity method are summarized. Analysis of the shortcomings of the method of deriving frequency compression ratio from static factors in the design of seismic wave similarity relation. The Duhamel integral analytic expression of the structure motion equation under earthquake is analyzed. The seismic response of the structure is closely related to the natural vibration frequency of the structure. A design method using frequency as input seismic wave similarity design control quantity is proposed. The natural vibration frequencies of the prototype and the model are studied by means of the Gonza landslide field ground pulsation test and the model white noise excitation. A new frequency compression ratio design scheme is given from the perspective of dynamic similarity. It is of great reference significance to optimize the dynamic similarity design of shaking table model test and improve the accuracy of test results.

Modelling the spatial population structure and distribution of the queen conch, Aliger gigas, on the Pedro Bank, Jamaica

The estimation of reliable indices of abundance for sedentary stocks requires the incorporation of the underlying spatial population structure, including issues arising from the sampling design and zero inflation. We applied seven spatial interpolation techniques [ordinary kriging (OK), kriging with external drift (KED), a negative binomial generalized additive model (NBGAM), NBGAM plus OK (NBGAM+OK), a general additive mixed model (GAMM), GAMM plus OK (GAMM+OK) and a zero-inflated negative binomial model (ZINB) ] to three survey datasets to estimate biomass for the gastropod Aliger gigas on the Pedro Bank Jamaica. The models were evaluated using 10-fold cross-validation diagnostics criteria for choosing the best model. We also compared the best model estimations against two common design methods to assess the consequences of ignoring the spatial structure of the species distribution. GAMM and ZINB were overall the best models but were strongly affected by the sampling design, sample size, the coefficient of variation of the sample and the quality of the available covariates used to model the distribution (geographic location, depth and habitat). More reliable abundance indices can help to improve stock assessments and the development of spatial management using an ecosystem approach.

New Results on Dissipative Control for a Class of Singular Takagi–Sugeno Fuzzy Systems With Time Delay

This article studies the problem of dissipative control for singular Takagi–Sugeno fuzzy systems with time delay. In order to reduce the conservatism brought by the time delay, we choose a proper augmented Lyapunov–Krasovskii functional and the auxiliary-function-based integral inequality to analyze the admissibility and dissipativity of the system. The singularity of the derivative matrix of the system leads to the matrix coupling terms, which are difficult to handle in the controller design by using the common controller design methods, so we propose an iterative algorithm to solve the controller parameters. The sufficient conditions of ensuring that the closed-loop system is admissible and dissipative are presented. Finally, three persuasive examples are given to demonstrate the effectiveness of the proposed method.

Common Problems and Design Methods of Urban Municipal Road Design

Common Problems and Design Methods of Urban Municipal Road Design

Brief Discussion on Common Problems and Design Methods of Urban Municipal Road Design

Brief Discussion on Common Problems and Design Methods of Urban Municipal Road Design

Designing the collective non-local responses of metasurfaces

The ability to design the electromagnetic properties of materials to achieve any given wave scattering effect is key to many technologies, from communications to cloaking and biological imaging. Currently, common design methods either neglect degrees of freedom or are difficult to interpret. Here, we derive a simple and efficient method for designing wave–shaping materials composed of dipole scatterers, taking into account multiple scattering effects and both magnetic and electric polarizabilities. As an application of our theory, we design aperiodic metasurfaces that re-structure the radiation from a dipole emitter: (i) modifying of the near-field to provide a 4-fold enhancement in power emission; (ii) re-shaping the far-field radiation pattern to exhibit chosen directivity; and (iii) the design of a discrete Luneburg–like lens. Additionally, we develop a clear physical interpretation of the optimised structure, by extracting eigen-polarizabilities of the system, finding that a large eigen-polarizability corresponds to a large collective response of the scatterers.

Implementing the principles of operating processes schematization and of performance loss distribution when designing long-stroke reciprocating compressor stages

To compress gases up to 10.0 MPa and higher, diaphragm and multistage reciprocating compressor units are used. They are heavy, massive and complicated. The results of analyzing laboratory examples of slow-speed long-stroke stages of reciprocating compressors while gas pressurizing up to such pressure have shown the possibility of solving the problems mentioned. Such stages differ from others, that is why we cannot use common design methods in this case. The performance design method for slow-speed long-stroke compressor stages with a discharge pressure of up to 10.0 MPa is based on the well-known principles of schematization of operating processes and distribution of performance losses. With regard to the experimental studies results (indicator and temperature diagrams, integral characteristics) we have found: the volumetric efficiency, which characterizes the ratio between real and theoretical compressor performance, its main components: the volume coefficient, the pressure coefficient, the temperature coefficient, and the leakage coefficient. Dependences are obtained for calculating these coefficients, which differ significantly from the known dependences for calculating high-speed compressor stages. The analysis of the influence of various factors on the performance losses of low-capacity long-stroke compressor stages of medium and high pressure revealed that the gaps in the working chamber have the maximum impact on the performance losses, the leakage coefficient significantly depending on the discharge pressure change. The volume coefficient has much less impact due to the increased stroke-to-diameter ratio of the piston, which provides a small amount of relative dead volume. The developed method can be used for preliminary calculation of compressor stages of the considered type.

Improving Competency in Tourism Industry by Achieving Pleasurability in Hotel Room's Design

Modern technology which is used in the interior design contributed greatly to meeting the needs of the human being, interacting with him and imparting pleasure and luxury to him, as it worked to make the Hollow spaces interact with the users and respond to their activities with many varied and positive images. Which necessitated the interior designer to review the common design methods in order to integrate with modern technology. This research reviews elements of achieving pleasure in the interior design of hotel rooms through the integration of modern technology, to meet the needs and requirements of users interactively, and to achieve the maximum benefit from the available spaces and achieve pleasure and luxury for users and improve their experience, so as to facilitate the occurrence of meaningful activities for the user through design for fun and comfort. This research followed the descriptive analytical approach, through studying some modern technological applications that contribute to achieving pleasure and luxury for users of hotel rooms, in addition to determining the extent of the impact of employment of technological applications on the user’s decision on how to choose the hotel. One of the most important results of this research was that the successful selection of the uses of modern technology applications which comply with the determinants of internal spaces, and their ability to link the hotel’s components and facilities and are appropriate for all the targeted activities within them, allowing the freedom for the users to control the space and the internal environment.

Dynamical distributed control and synchronization

It is well known that most of real-world phenomena are described by partial differential equations. Nevertheless, for control design purposes it is very common to approximate them with a set of ordinary differential equations, since conventional design methods, such as calculus of variations or differential geometry, turn out to be very complex for this class of systems. However, by doing this, valuable properties are lost. In this work, we present a dynamical distributed control for nonlinear partial differential equation systems and we focus on solving the Generalized Synchronization problem, since this topic has multiple applications in the disciplines of engineering, biology, physics, etc. For the design of the control, we utilize a differential algebraic approach. The key ingredient of our design method is to find a canonical form of the given systems by means of the so-called partial differential primitive element. This representation is known as Generalized Observability Canonical Form and allows us to design a dynamical distributed control in a natural way. Additionally, to avoid a functional analysis for the stability of the resultant synchronization error, we propose to utilize tools from semi-group and spectral theory of infinite dimensional systems in a Hilbert space. As a result, we present a design approach less complex and, therefore, more accessible than most common design methods. Besides, with the proposed stability analysis, we obtain an easy criterion to select the control gains; hence, we can solve the generalized synchronization problem of partial differential equation systems in a simple way. To validate the effectiveness of the proposed control, we present two examples of generalized synchronization for reaction-diffusion systems and show their respective numerical results.

A framework for the use of reliability methods in deep urban excavations analysis

Deep excavations in urban areas impose deformation to adjacent structures; hence the reliability of deformation analysis for the real deep excavation projects is very important to be assessed. In this study a framework is presented for the use of reliability methods in deformation analysis of deep urban excavations. The suggested framework is applied for 5 real deep excavation projects implemented during last 10 years. All studied cases were recognized as projects of high importance in urban areas, and were monitored during the excavation process. A non-probabilistic reliability analysis procedure, Random set method, in combination with finite element numerical modeling is applied to obtain the probability of unsatisfactory performance for each case. The reliability analysis results are confirmed by field observations and measurements. Typical results for the probability of analytical deformations exceeding the acceptable values along with the site observations and measured displacements for 5 real deep excavation projects show that the reliability analysis could be a beneficial tool for designer. It is concluded that applying the suggested framework in the design stage of deep excavation projects may lead to design more appropriate systems compared to common deterministic design methods.

A review of the application of active noise control technologies on windows: Challenges and limitations

Traffic, construction and industry noises are the main sources for noise pollution for mega cities. These noises mainly propagate through the windows of the dwelling and can degrade the comfort level of a living space. Various studies have demonstrated that the active noise control (ANC) system is a potential technique which can be applied on the windows in order to mitigate environmental noise level inside a building. The present paper attempted to give a detailed description for the use of ANC system in windows under various scenarios, namely closed, fully opened and partially opened windows. For closed windows, the most common design methods of ANC system are cavity and panel controls. For opened window, the secondary source is either mounted on the frame of the window or implanted in the walls. For partially opened windows, the most common design method is cavity control. Advantages and shortcomings of various ANC designs were presented and discussed in the present study.

A Product Development Approach Advisor for Navigating Common Design Methods, Processes, and Environments

Many different product development approaches are taught and used in engineering and management disciplines. These formalized design methods, processes, and environments differ in the types of projects for which they are relevant, the project components they include, and the support they provide users. This paper details a review of sixteen well-established product development approaches, the development of a decision support system to help designers and managers navigate these approaches, and the administration of a survey to gather subjective assessments and feedback from design experts. The included approaches—design thinking, systems thinking, total quality management, agile development, waterfall process, engineering design, spiral model, vee model, axiomatic design, value-driven design, decision-based design, lean manufacturing, six sigma, theory of constraints, scrum, and extreme programming—are categorized based on six criteria: complexity, guidance, phase, hardware or software applicability, values, and users. A decision support system referred to as the Product Development Approach Advisor (PD Advisor) is developed to aid designers in navigating these approaches and selecting an appropriate approach based on specific project needs. Next, a survey is conducted with design experts to gather feedback on the support system and the categorization of approaches and criteria. The survey results are compared to the original classification of approaches by the authors to validate and provide feedback on the PD Advisor. The findings highlight the value and limitations of the PD Advisor for product development practice and education, as well as the opportunities for future work.

The Impact of Using Interactive Interior Design on Enhancing the Performance of Clothing Shop

The interior designer is facing many challenges in the design process, to make the interior fit to the environmental and cultural conditions, and thanks to modern technology, which led to successive architectural transformations in response to the many developments in ICT, many new concepts have emerged in the field of interior design, that seek to meet human needs and future requirements. One of these concepts is interactive interior design, which necessitated the interior designer to reconsider the common design methods in order to integrate with the era of digital design. Whereas the interactive design has given shape, space and function a new meaning, it is possible to have an interaction between spaces and humans, taking into account the respect of the internal and external environment. The research reviews the impact of using interactive design on space handling in clothing stores. By employing an interactive design in the interior spaces, to meet the needs and requirements of users and make the most of the available spaces and achieve luxury. Whereas the use of interactive design in the determinants of the internal space of clothing stores work to solve the prevailing problems in the accumulation of spaces in the display and congestion of corridors customers and do not direct them the best direction to achieve the highest sales. Follow the Methodological, descriptive and analytical research of models of shop that sell clothes to identify the most important design problems that exist. The most important results were: 1. The use of interactive techniques as a guide and advertising inside the shops of clothing has facilitated the process of selecting clothes inspection and purchase without the need for spaces to change clothes. 2. The use of interactive technologies led to the organization of the sale and display of customers and the lack of congestion in the places of assembly.

Research on Design Method Optimization of Combined Sewer Overflow Detention Tank

Detention tank is widely used in urban waterlogging control, rainwater runoff pollution control, combined sewer overflow (CSO) control and rainwater utilization, etc. For detention tanks in different types or functions, their design methods, construction forms and ways of operation and management are very different. In recent years, many cities in China have begun to apply or plan to build CSO detention tanks to control the CSO pollution, but there are still many problems and puzzles in designing the tank. This paper summarizes and evaluates the common design methods of CSO detention tank at China and abroad. Based on the physical projects in which the author has participated in, the scale and control effect of the CSO detention tank are studied by model simulation, taking a combined sewer system catchment in the Beijing old city as examples. Based on the analysis, the long-term simulation method is recommended for designing of CSO detention tanks in China, and a design criteria suitable for a larger range can be determined through research and analysis of a typical and representative area if there is no way to research every area. At last, several key factors that affect greatly the scale and pollutant control efficiency of CSO detention tank are summarized and analyzed, including objectives of CSO control, rainfall characteristics, CSO pollutants transport law, interception multiple, capacity of wastewater treatment plant, space conditions and investment, layout of detention tank and operation mode of detention tank. Hope to provide reference for the scientific designing of CSO detention tank and realize cost-effectively controlling CSO in cities of China.

Chaotic vibration reduction of vertically suspended centrifugal pumps by the effect of the mechanical design parameter on hydraulic forces

The chaotic vibration generated by slender rotor–stator contact in vertically suspended centrifugal pumps shows itself in wear and fatigue failure of shafts, bearings, wear rings, seals and impellers. In common design methods of rotary equipment, for validating designed products, virtual representations in Computer Aided Design tools are imported to simulation tools (e.g. ANSYS software) on the last step of the design process. In this research, the ability of a non-linear finite element model is examined to support decision-making, synthesis and interaction of design choices during earlier stages of design process. So, the back wear ring diameter as the adjustable mechanical design parameter is used to reduce chaotic behavior of the pump rotor without any difficulty in manufacturing or problematic effect on the major hydraulic properties. The non-linear finite element model of the rotor is discretized into an appropriate number of Timoshenko beam elements. The major non-linear terms, the geometric stiffening effect, and the gyroscopic effect are considered. Rotor–stator contact, considering the rotor–stator clearance and the rotor–stator friction coefficient are taken into account. The full-order equations of motion are obtained using Lagrangian approach and the finite element method, and then are integrated into a computational plan. This study presents an allowable domain of the mechanical design parameter in which chaotic vibrations of the slender rotor can be reduced effectively. Furthermore, this research shows a basic method in which some design stages can be run in parallel rather than in series can be used to reduce redesigning and optimization times.

Predicting deformation of multipropped excavations in soft clay with a modified mobilizable strength design (MMSD) method

Although serviceability (i.e., deformation) governs the performance of deep excavations in urban areas with soft clay deposits, the common design methods are only able to check the potential of base stability, rather than the deformation. This limitation has led to the development of an analytical approach entitled the mobilizable strength design (MSD) method, which can predict both serviceability and safety in a single step of calculation. The modification of the MSD method (i.e., the MMSD method) was recently made by the authors, by implementing a more realistic plastic deformation mechanism into the calculation. The objectives of this study are (a) to validate the MMSD method by comparing its predicted deformation with eight well-documented case histories in Shanghai and Hangzhou soft clay and (b) to quantify the influence of some potentially important factors on the deformation of deep excavations in Shanghai and Hangzhou. The accuracy of the MMSD predictions for the maximum lateral wall displacement (δh-max) have been found to fall within 35% of the field data in most of the cases. This accuracy is more satisfactory than the accuracy (i.e., 120%) of the MSD predictions for the corresponding case histories, suggesting the effectiveness of the modified plastic deformation mechanism considered in the MMSD calculation. Based on the verified MMSD method, preliminary design charts that predict δh-max of narrow excavations (specifically for a metro station) considering different geometries and strength mobilization characteristics have been developed.

A new design method for propeller mixers agitating non-Newtonian fluid flow

The common design methods for mixers agitating non-Newtonian fluid flow are not suitable for developing a completely new geometrical shape. These design methods were originally intended only to scale an existing mixer with several correlation methods. For this, the dimensionless power characteristics of the mixer is first determined for agitating Newtonian fluid flow. Subsequently, for the desired operating conditions, the apparent viscosity of the non-Newtonian fluid is derived using the mentioned correlation principles. After setting the desired geometrical parameters, it is possible to calculate the apparent Reynolds number. By comparing the apparent Reynolds number with the dimensionless power characteristics, the estimated power consumption and, therefore, the engine to drive the mixer can be determined. This procedure comes with the assumption of a valid correlation between Newtonian and non-Newtonian fluid flow, which is not physical. Furthermore, the question of how to develop the geometric shape of a mixer for a considered operation point is still open. In this paper, a new method is introduced to develop the shape of a propeller mixer for arbitrary operating conditions in pseudo-plastic fluids by analytical methods. The method is based on the consequently implemented blade element momentum theory.