Structural Design Method Research Articles

Study on ultimate capacity and design method of cold-formed steel equal lipped angle components under axial compression

This study focuses on evaluating the load-bearing capacity of cold-formed steel (CFS) equal lipped angle components. It delves into the structural behavior and design methods, taking into account various edge conditions and buckling modes. By considering the key parameters, which are component length, component thickness, total lip length, and lip bending angle, a total of 555 numerical models are developed for a systematic analysis on the components with two types of cross-sectional shapes. Since the coefficients within the direct strength method (DSM) inadequately capture the ultimate load-bearing capacity of lipped angle components, we introduce a design methodology rooted in the DSM framework to address global and global-local coupling buckling modes while imposing constraints to prevent local-distortion coupling buckling modes. The machine learning models (XGBoost, BPNN, and 1D-CNN) are adopted to predict the structural behavior of the two types of lipped angle components. These models can integrate the analysis of the components with two types of cross-section shapes in predictions of ultimate load capacity, axial deformation, and buckling modes. Meanwhile, the prediction accuracy of the machine learning models surpasses that of the analytical design methodology, offering more accurate prediction for ultimate load capacity, axial deformation and buckling modes.

INFORMATION SYSTEM DATA MANAGEMENT INCENTIVES EDUCATORS AND EDUCATORS AT PERMATA BANGSA KINDERGARTEN

The report on educator and educator incentive data that is currently running at TK Permata Bangsa is still done manually, namely collecting files and making data recaps for submitting lists of incentive recipients both education and educators are still recorded and made using Microsoft Excel. The collection of files and documents is done separately, this causes delays because it takes a long time. Teachers as educators and educators sometimes forget and are busy preparing the requested files. The research conducted seeks to provide solutions in processing data on educational incentives and educators, an application system that can be accessed easily. The information system created in the form of a web-based application will assist the school in making data reports on educational incentives and educators. The result of this study is in the form of an application that can be accessed through a browser. The research methodology used in the preparation of this thesis is direct interviews, observations and literature studies while the system development stage uses the Waterfall method. To design this application, a structural design method is used, namely Unified Modelling Language (UML).

Extended multiscale FEM-based concurrent optimization of three-dimensional graded lattice structures with multiple microstructure configurations

In this work, a novel concurrent design method for three-dimensional graded lattice structures considering multiple microstructure configurations is proposed. Firstly, the Multiple Variable Cutting (M-VCUT) level set method is employed to represent the geometry of lattice microstructures and define the optimization parameters. Then, the extended multiscale finite element method (EMsFEM) is implemented for calculating the equivalent stiffness matrices of microstructures in offline form. Compared with the traditional homogenization-based multiscale approaches, the proposed method eliminates the scale separation assumptions and takes into account the coupling effects in different directions of materials. In addition, a data-driven method and a parallel computing approach are integrated together so that computational efficiency can be greatly improved. After the iteration process, the optimized full-scale graded structures are reconstructed using interpolation technology to generate well-connected microstructures in neighboring cells. Finally, several 3D numerical examples are utilized to validate the effectiveness of the proposed method, where multiple lattice microstructure configurations are considered, including truss-lattices and plate-lattices.

Geometry-force interactive design and optimization method of cable dome structures

Cable dome is a typical flexible structural system. Its initial geometry determines the prestress distribution and affects the structural performance. Using geometric parameters to establish the mechanical equation of initial state can effectively realize the geometric-force interactive design and optimization of cable dome structure. Consequently, a standardized equation is established in this paper to uniformly express the geometric-force relationship, utilizing a feasible prestress distribution function expressed by geometric parameters. Subsequently, an interactive design method for initial geometry and prestress is presented. The proposed method is theoretically expounded in terms of geometric design, prestress design and shape optimization. Two typical cable dome cases, Geiger and Levy, are successfully applied to accomplish the geometric-force design and optimization of the initial state. The results show that the efficient design of initial state can be completed by establishing the interaction between geometry and force without repeated algebraic calculation. The optimized initial geometry can significantly improve the Structural stiffness.

A non-uniform lattice design method for lightweight structures in 3D printing

Lightweight design is an essential topic in aerospace, automotive and other fields. In automobile manufacturing, the engine connecting rod is one of the main components; its lightweight design has a high reference value. And 3D printing provides a feasible solution for designing and manufacturing lightweight structures. Unlike the traditional geometrically homogeneous point design, this study offers a non-homogeneous point design method based on the spatial stress state of additively manufactured components. After numerical simulation of quasi-static stresses on a model of an engine connecting rod, finite element grid cells with different stress values are replaced by lattice cells with different specific stiffnesses at similar local stress levels. The overall specific stiffness of the structure is further improved by continuing the optimized design with the corresponding gradient-type reinforcement of the non-uniform lattice structure. The basic idea of this design is to perform non-uniform adaptive filling of solid parts under localized loading by employing different types of unit cells. Stereolithography 3D printing technology prepares the engine lattice structural parts for quasi-static compression comparison experiments and fracture analysis after failure. The conclusions show that the engine connecting rod members with non-homogeneous lattice have more excellent overall mechanical properties than homogeneous lattice members. This work demonstrates the feasibility of such design methods for 3D printing lightweight structures and optimization.

Design and optimization of origami-inspired inflatable deployable tubular structures

Inflatable deployable structures inspired by origami have significant applications in space missions such as solar arrays and antennas. In this paper, a generalized Miura-ori tubular cell (GMTC) is presented as the basic cell to design a family of inflatable origami tubular structures with the targeted configuration. First, the classification of rigid foldable degree-4 vertices is studied thoroughly. Since the proposed GMTC is comprised of forming units (FU) and linking units (LU), types of FUs and LUs are investigated based on the classification of degree-4 vertices, respectively. The rigid foldability of the GMTC is presented by studying the kinematics of the FUs and LUs. Volume of the GMTC is analyzed to investigate multistable configurations of the basic cell. The variations in volume of the GMTC offer great potential for developing the inflatable tubular structure. Design method and parametric optimization of the tubular structure with targeted configuration are proposed. The feasibility of the approach is validated by the approximation of four different cases, namely parabolic, semicircular, trapezoidal, and straight-arc hybrid tubular structures.

Research on chip flute design of variable pitch variable helix end milling cutter based on manufacturability

In this paper, a design method of chip flute structure of variable pitch variable helix (double variable) end milling cutter based on manufacturability is presented, which aims to improve the dynamic balance and milling performance of the tool. The feasible region for grinding the chip flute of a double variable end milling cutter is obtained by solving the numerical model for the shape of the radial cross-section curve of the chip flute, along with the position and orientation of the grinding wheel. The multiple tool-walking grinding method is proposed to avoid the interference and edge cutting between the grinding wheel profile and the chip flute section, and the chip flute structure design criterion is obtained. The error between the grinding simulation results and the design target parameters is about 1 %, which verifies the effectiveness of the design criteria. With the double variable end milling cutter designed by this criterion, the milling vibration amplitude is reduced by about 21 %, and the average surface roughness of the workpiece is reduced by 9.872 μm. The chip flute structure design method proposed in this paper not only meets the manufacturing feasibility, but also effectively improves the milling performance of the tool. On the premise of considering manufacturability, the design method of chip flute as the optimization objective provides a new idea for tool structure design.

Prestress Iterative Design and Precision Control Method for Cable-strut Structures using Enhanced Differential Evolution

Prestress Iterative Design and Precision Control Method for Cable-strut Structures using Enhanced Differential Evolution

Comprehensive study on fail-safe topological design method for 3D structures

Comprehensive study on fail-safe topological design method for 3D structures

A Unified Controller Design Method for Multiple Control Structure with Perspective to Parametric Independent Control of Boost Converter

A Unified Controller Design Method for Multiple Control Structure with Perspective to Parametric Independent Control of Boost Converter

Kirigami-inspired, three-dimensional piezoelectric pressure sensors assembled by compressive buckling

Piezoelectric sensors whose sensing performances can be flexibly regulated hold significant promise for efficient signal-acquisition applications in the healthcare field. The existing methods for regulating the properties of polyvinylidene fluoride (PVDF) films mainly include material modification and structural design. Compared to material modification, which has a long test period and an unstable preparation process, structural design is a more efficient method. The irigami structure combined with compressive buckling can endow the flexible film with rich macrostructural features. Here, a method is fabricated to modulate the sensing performance by employing distinct 3D structures and encapsulation materials with varying Young’s moduli. The relationship among the aspect ratio (α), pattern factor (η), elastic modulus of encapsulation materials, and equivalent stiffness is obtained by finite element simulation, which provides theoretical guidance for the design of the 2D precursor and the selection of encapsulation materials. In the demonstration applications, the sensor accurately captures pulse waveforms in multiple parts of the human body and is employed for the pressure monitoring of different parts of the sole under various posture states. This method of structure design is efficient, and the preparation process is convenient, providing a strategy for the performance control of piezoelectric pressure sensors.

Research on the design and balancing strategy with multi-section lithium battery protection IC

This study uses 0.5um BCD technology to design a multi section lithium battery protection chip suitable for small mobile electronic devices such as Bluetooth earphones and smart bracelets. By providing a complete system structure diagram, the principles and design methods of several key circuits in the chip were introduced. This chip can effectively monitor the voltage of lithium batteries, take protective measures against abnormal situations such as overcharging, discharging, and overcurrent, and has a balancing module with dynamic power consumption management function. The balancing module adopts a passive balancing architecture, and the balancing algorithm used is an average based voltage detection algorithm. Using this algorithm can make the balancing system structure simple and reduce system power consumption, reduce the differences between batteries within the group, and thus improve the uniformity of the battery pack. The overcharging detection accuracy of the designed chip is ±25mV, the overcharging detection accuracy is 50mV, and the static working current of the chip is 7uA.

Research on Key Problems and Optimization Based on Structural Design of Super High-rise Buildings

At present, complex super high-rise buildings and super high-rise buildings are emerging all over China, but there are still many problems to be solved in the design of super high-rise structures. For example, the wind pressure and earthquake risk of high-rise buildings, fire safety issues and personnel evacuation issues, earthquake will produce greater inertia force and bending force in high-rise buildings, wind load and wind pressure effect will be more significant, these are the parts that need to be carefully considered to ensure the safety and stability of the building structure. Therefore, it is necessary to analyze and optimize the problem of high-rise buildings. Taking a super high-rise building in Luohu District of Shenzhen City as an example, this paper analyzes the basic structure of super high-rise building, analyzes the key problems of structural design, and discusses the optimization method. This paper puts forward the optimization design method of building structure for seismic problem of super high-rise building structure, puts forward the solution to wind resistance problem, and puts forward the optimization layout method of building fire protection.

Research on Topology Optimization Design of Truss Structure

Due to continuous advances in engineering technology and architecture, the use of truss structures is expanding. The design method of ideal truss structure is the main research topic of this paper. The topology optimization method is applied to a bridge design case study. The load and total material utilization ratio of each rod of triangular truss, arch truss and Pratt truss were determined by using structural mechanics solver. By comparing the stress and material consumption of the truss structure, it shows that the truss structure has advantages in stress and can be used in the truss construction of short-distance arch bridge. Truss is the basic unit of the topology optimization method of truss structure proposed in this study. By optimizing the topological shape of the truss, the ideal design of the whole structure is realized. While maintaining structural stiffness and stability, the technology can significantly reduce the weight and cost of the structure.

An acoustic impedance design method for tubular structures with broadband sound insulations and efficient air ventilation

In this research, we proposed an acoustic impedance-based design method to increase the soundproofing bandwidths and maintain efficient air ventilation for tubular structures consisting of hollow air-flowing channels. This research has great potential to provide design guidelines based on an acoustic impedance model and even/odd mode analysis for hollow-tube ventilated devices containing resonance and antiresonances. We introduced a thin ventilated structure with a subwavelength thickness of 0.107 λ where λ corresponds to the lowest frequency within the filtering bandwidth, a 19.4 % cross-section open for air passage, and a 10 dB fractional bandwidth of 110.2 % (i.e., 90 % sound energy is blocked), which is broader than that of a conventional Fano-like structure of 44.7 %. To experimentally verify the proposed approach, two prototypes, including lateral-coupled and longitudinal-coupled devices, were designed, fabricated with 3D printing, and experimentally characterized via a commercial-available impedance tube system. The simulations matched the measurements and demonstrated the 10 dB fractional bandwidth of 65 % and 91.5 % and ventilation efficiencies of 21.4 % and 33.4 %, respectively. The main contribution of this work is that the proposed approach can be adopted for lateral or longitudinal coupled ventilated structures with broadband sound insulations and lower the effects of resonance-induced sound transmissions. Besides, the proposed acoustic-impedance model can significantly save the required tremendous computational resources and time compared to FEM simulations. Moreover, the proposed lateral and longitudinal ventilated structures are expected to benefit broadband sound filtering and noise reduction for thin panel or tubular silencers

Investigation on the mechanism and a universal structural design method for resistive switching devices

Resistive random-access memories have attracted significant attention in memory applications, while the physical mechanism behind their resistive switching behavior is still unclear. As a key issue, the migration of oxygen vacancies (VO) directly influences the performance of devices in the formation and rupture of conductive filaments (CFs). In this work, the distance of VO migration is performed as electric field dependent and affects the performance of the device. Sufficient distance of VO migration is essential for formation and rupture of CF completely, leading to, ideally, SET/RESET transition of the device. Based on this mechanism, an enhanced electric field is designed that optimizes the stability of the device significantly, which is demonstrated to be a promising approach to optimize the properties of the device. The investigation is helpful for guiding the design of device structures.

Research on the Reform of the Course “Fundamental Principles of Engineering Structures” in the Context of School-Enterprise Cooperation and Integration of Production and Education

The course “Fundamental Principles of Engineering Structures” is one of the compulsory courses for undergraduate students majoring in civil engineering, structural engineering, and bridge engineering. It mainly introduces the basic concepts, principles, and design methods of engineering structures. The course’s emphasis lies in the integration of theory and practice, aiming to enable students to acquire fundamental theoretical knowledge of engineering structures in the classroom and to consolidate this knowledge through practical activities such as experiments and design, thereby enhancing their comprehensive abilities. Therefore, the teaching reform of the course on fundamental principles of engineering structures should start with improving students’ practical abilities and strive to achieve organic integration of theory and practice. This paper explores how the teaching reform of the course should be conducted against the backdrop of course ideological and political education, mainly focusing on the integration of school-enterprise cooperation and production-education integration. Firstly, the author analyzes the current issues and challenges from the perspectives of school-enterprise cooperation and production-education integration, and then proposes corresponding measures for the reform of course teaching, including establishing a curriculum system in line with modern engineering practices, fully leveraging the role of teaching design, and stimulating students’ interest in learning, among others. It is hoped that this research can provide some reference and inspiration for developing relevant teaching reforms in the course of fundamental principles of engineering structures.

Optimization of MTI structure based on material characteristics under extreme aerodynamic heating environment

Thermal insulation structure is a key factor to protect a high-speed aircraft to work safely and complete various tasks. The multilayer thermal insulation (MTI) structure has attracted much attention because of its light weight and good thermal insulation effect. The performance of an MTI structure is not only related to its physical sizes, but also closely related to the material optimization and temperature influences. A transient nonlinear thermal transfer model of the MTI structure is established, and a numerical solution strategy of the nonlinear thermal transfer model is proposed. Considering material selection, introducing the temperature influence of materials, and taking the geometric dimensions and equivalent mechanical properties of the MTI structures as constraints, an optimization frame of the MTI structures is established. Then two intelligent methods are adopted to solve the problem. Using the aerodynamic heating environment of X-43 flight trajectory, the results of a typical high-speed aircraft show that the proposed optimization framework can reduce the structural mass density from 13.95 kg‧m−2 to 9.10 kg‧m−2 by about 34.8 %. The temperature effect analysis shows that the temperature variation has an important influence on the optimization results. If the temperature effect on material properties is not considered, the optimized design scheme may not meet the temperature design constraints (The maximum temperature of the inner surface is 410 K, far exceeding the maximum allowable temperature of 320 K) which further leads to structural failures. Finally, the reliability and rationality of the optimization scheme are verified by a finite element model (FEM). The equivalent modulus of the optimized MTI structure is 146 GPa and the mass area density of the MTI structure is 7.7 kg‧m−2. The optimization design method of an MTI structure proposed in the current paper provides a technical support and lays a foundation for the overall design of a high-speed aircraft.

Analysis and reduction of electromagnetic vibration in integral-slot PM machine by functional magnet structure

It is significant to balances torque and vibration performance for the surface-mounted permanent magnet (PM) machines. This paper proposes a functional magnet structure to suppress the vibration response of integral-slot surface-mounted PM machines. At the same time, the torque ripple is also greatly reduced without sacrificing the average torque. Firstly, taking the 48-slot/8-pole PM machine as an example, the main sources of the air-gap radial force are analyzed based on the Maxwell stress equation. Thereby, the main PM flux density harmonic components that contribute to the radial force are pointed out. Secondly, the design method of different functional magnet structure is investigated. Then, the effects of different magnet shapes on the torque and vibration performances are compared. The result shows that the proposed sinusoidal+3rd-order harmonic injection functional magnet structure can effectively improve the vibration performance without sacrificing the average torque. Finally, the prototype of the 48-slot/8-pole PM with functional magnet structure is manufactured, and the experiments are carried out for validation.

Shell-infill composite structure design based on a hybrid explicit- implicit topology optimization method

The present paper introduces a hybrid explicit–implicit topology optimization method for shell-infill composite structure design. The proposed approach effectively combines the advantages of the explicit Moving Morphable Component (MMC) method, which describes structural topology only using a set of geometric parameters, and the implicit Solid Isotropic Material with Penalization (SIMP) method, which offers greater design freedom for characterizing the structural features. Compared to the existing methods for shell-infill structure design, the proposed approach can obtain optimized shell-infill structures with complex infill topology without resorting to complex filtering/projection operations. Numerical examples demonstrate the effectiveness of the proposed approach.