Structural Optimization Analysis Research Articles

A gradient-based optimization method with functional principal component analysis for efficient structural topology optimization

Structural topology optimization (STO) is usually treated as a constrained minimization problem, which is iteratively addressed by solving the equilibrium equations for the problem under consideration. To reduce the computational effort, several reduced basis approaches that solve the equilibrium equations in a reduced space have been proposed. In this work, we apply functional principal component analysis (FPCA) to generate the reduced basis, and we couple FPCA with a gradient-based optimization method for the first time in the literature. The proposed algorithm has been tested on a large STO problem with 4.8 million degrees of freedom. Results show that the proposed algorithm achieves significant computational time savings with negligible loss of accuracy. Indeed, the density maps obtained with the proposed algorithm capture the larger features of maps obtained without reduced basis, but in significantly lower computational times, and are associated with similar values of the minimized compliance.

Vibration test and structural optimization analysis of axle box bracket

The bracket cracked and ground cable broken have occur to axle box many times on certain line metro vehicle. In view of this kind of accident, vibration test, vibration analysis, modal analysis as well as structure optimization are carried out for the axle box bracket of the subway. The test results show that the first transverse bending mode of the bracket is excited by the line vibration, so, it breaks due to vibration fatigue in the resonant state. The simulation results show that the modal frequency can be increased by thickening the bracket and optimizing its structure, so that avoiding resonance phenomenon and increasing its fatigue life. Finally, experiments are carried out to further verify the conclusion, and the structure that performs best can be chosen among multiple optimizations.

The Impact of Construction Industry Structure Optimization on the Economy of Metropolitan Area - Taking Hefei and Nanjing Metropolitan Area as Examples

This research selected Hefei and Nanjing metropolitan area as the research object to analyze the optimization of construction industry structure in Hefei and Nanjing metropolitan area in 2018. Firstly, the construction industry structure rationalization analysis, heightened analysis, specialization analysis and similarity analysis were conducted for Hefei and Nanjing metropolitan areas, then the theory of construction industry structure optimization analysis was derived for Hefei and Nanjing metropolitan areas, and then ArcGIS technology was used to draw the spatial distribution map of construction industry structure in the two metropolitan areas to provide theoretical support for industrial structure optimization and high-quality construction of Hefei metropolitan area. Finally, the analysis concluded that in the process of synergistic development, the Hefei metropolitan area should focus on strengthening the synergistic development with Nanjing metropolitan area, so that the Yangtze River Delta region can achieve the optimization of economic structure preferably, advanced industrial base and modernization of industrial chain, and enhance the coordination of urban and rural regional development, thus making significant progress in the construction of modernized economic system.

Coupling Spatial Distribution and Industrial Structure Optimization Analysis of Economic and Environmental Pollution in Chongqing

In recent years, as one of the old industrial bases in China, although it has been promoting the construction of new industrialization, Chongqing is still facing a more severe situation of industrial pollution. In order to further upgrade the optimization of industrial structure in Chongqing, the paper combined with 2773 cases of Chongqing pollution administrative penalties. Select industrial pollution enterprises administrative penalty amount of the 38 districts and counties in Chongqing as cross-sectional data, the spatial correlation of industrial pollution in Chongqing was analyzed by exploratory spatial analysis. Then, using the coupled coordination degree model, the evaluation index system of economic development and industrial pollution coupling degree in Chongqing area is established, and the spatial pattern of the economic environment coupling degree in Chongqing is analyzed. It is found that the spatial agglomeration characteristics of industrial pollution in Chongqing are not obvious, and the regional pollution is different, the economic environment system is in the state of low coupling, the spatial types of the coupling degree of regional economic environment are the most antagonistic economic environment, and the minority is the low coupling region. Based on the results of spatial layout, this paper analyzes the industrial structure of Chongqing City and put forward the optimization strategy of industrial structure.

Analysis of the thermal effect of a lithium iron phosphate battery cell and module

AbstractBased on the theory of porous electrodes and the properties of lithium iron batteries, an electrochemical‐thermal coupling model of a single cell was established. The model was mainly used to study the temperature rise and temperature distribution characteristics in different regions of lithium iron batteries under different working conditions. In addition, a heat dissipation comparison analysis was carried out for different types of liquid cold runners, the optimal runner scheme was selected, and a structural optimization analysis was carried out. The simulation results show that the lithium iron battery discharges under the same ambient temperature and different C rates, and the battery temperature continuously increases with C. The temperature rise is mainly affected by Joule heat, and when the lithium iron battery is discharged at the same C but different ambient temperatures, the temperature rise of the lithium iron battery shows a decreasing trend with the increase in ambient temperature in a certain temperature range. The serial flow channel solution induces the best thermal behavior. Using the response surface optimization analysis, the three independent variable factors at which the temperature equilibrium R reaches the largest value under the liquid cooling module model are the rectangular flow channel length‐to‐width ratio, flow rate, and thermal conductivity.

Structural optimization and numerical thermal analysis of ultraviolet light-emitting diodes with high-power multi-chip arrays

In this paper, the finite element method and experiment were used to systematically study the influence of different factors on the heat dissipation of high-power ultraviolet light-emitting diode (UV LED) module, including chip spacing and structure, sub-mount, adhesive materials, the packaging area and void ratio of adhesive. The package structure was optimized by introducing Al barrier plate and changing the spacing between adjacent chips. Considering the balance of junction temperature and irradiance, the appropriate chip spacing (∼ 2.5 mm) should be chose. The simulations analysis demonstrated that both sub-mount and adhesive materials play an important role in the thermal performance of the UV LED module. The area ratio (∼0.9) between the adhesive area and the chip area can not only realize the excellent heat dissipation but also minimize the use of adhesive materials. During reflow soldering, the lager coalesced voids should be decreased as soon as possible, which have worse heat dissipation performance than the distributed voids. Furthermore, the reliability and validity of the numerical simulation were verified by the experiment data. The present conclusions provide significant insight on designing and optimizing high-power UV LED devices.

Structural Optimization and Finite Element Analysis of Swing Arm Plate Suction Device for Battery Packer

Aiming at the problem that the side mounting plate and the connecting plate of the swing arm type polar plate suction device in the upper plate mechanism of the battery pack machine are thick, Solidworks is used to optimize the structure of the upper plate mechanism, and Ansys finite element analysis software is used to carry out multi-objective optimization on the optimized side mounting plate and the connecting plate. The results show that adding two chamfers to the side mounting and adding a round corner to the corner of the connecting plate not only effectively reduces the weight and maximum equivalent stress of the plate suction device and solves the problem of stress concentration, but also obviously improves the working precision and production efficiency of the lead-acid battery pack machine.

Structural Simulation and Optimization Analysis of Electric Heater Based on Chimney Effect

The natural convection heater is a commonly used electric heater, which belongs to the chimney structure heater. In this paper, a three-dimensional model is built and simulated by the finite element analysis software. The influence of chimney height, vent size and vent shape on chimney effect was studied by orthogonal experiment. The simulation results show that the electric heater with 85 mm chimney height, 6 mm equivalent diameter of the vent and square shape of the vent has the best heat transfer effect. The simulation work can play a guiding role for the customization of electric heater structure.

Current State of Development of Ship Structural Design and Optimization Methods

This paper presents state-of-the-art methodologies and methods used in the rationally-based structural design of ships and offshore structures, namely design support system, structural optimization, surrogate modelling and sensitivity analysis. It demonstrates their application in structural design of a platform support vessel. It ends with a list of benefits that a structural designer may expect when the presented methods/methodologies are used. It also shows the obstacles to their full implementation in the engineering practice.

A class of biaxial micro/meso-scale structures for isotropic in-plane inertial sensing and actuation: design, fabrication and experiments

A micro/meso-scale monolithic architecture was designed, fabricated and tested for in-plane inertial sensing and actuation with isotropic stiffness in the sensitive plane and high frequency-ratios between the insensitive and sensitive directions. The architecture was designed to accommodate any regular polygonal shape with a proof-mass suspension made of a serial array of compliant parallelogram linkages. Structural optimization and finite element analysis were conducted to achieve high frequency ratios and a high degree of compliance in the sensitive directions, for low-g applications and in-plane sensing. Then, the elastically isotropic structure for any regular polygonal shape was modeled in the sensitive plane and validated numerically. Lame curves were introduced in the fillets to relax the stress concentration, while air-damping analysis was introduced to provide prediction of the high resistance in the insensitive out-of-plane motion. Next, the microfabrication process was devised and conducted for triangular and square structures based on the biaxial architecture. Special techniques were studied on the wafer bonding with large cavities and the adhesive influence during deep reactive-ion etching (DRIE). Finally, techniques were studied on the reflectivity adjustment of the sample surface and the in-plane biaxial motion detection of the fundamental frequencies using a uniaxial laser-sensing system. Vibration tests conducted in the micro/meso prototypes validated the isotropic biaxial sensitivity and the size effect of the high squeezed-film air damping in the insensitive direction.

Structural optimization and finite element analysis of poly-l-lactide acid coronary stent with improved radial strength and acute recoil rate.

Current poly-l-lactide acid (PLLA) scaffolds have issues of inadequate mechanical strength leading to thrombosis formation. Designing a novel bioabsorbable PLLA stent with a novel structure and improved mechanical property is urgently needed. In this study, stent structure modification and optimization based on bioresorbable vascular scaffold Version 1.1 (BVS 1.1, Abbott Laboratories) were conducted. The mechanical property of the redesigned stent was studied using both computerized finite element analysis and experimental mechanical deformation testing, including radial strength (RS), acute recoil (AR), foreshortening (FS), and bending stiffness (BS). The simulated and experimental results showed that the mechanical properties of the modified structure were significantly improved (modified stent vs. BVS 1.1: RS: 2.25 vs. 1.29 N/mm; AR: 3.03 vs. 4.41%; FS: 1.13 vs. 6.89%; BS: 1.49 vs. 0.72 N mm2 ).

Development of Multi Micro Holes Synchronous Rotating and Vibration EDM Machine Tool

In order to solve the problem of low efficiency of single electrode discharge machining, complex process and limited machining quality of group electrode array hole machining technology in traditional micro EDM machine tools, a multi-micro-hole synchronous rotating and vibration EDM machine tool was developed. The machine tool is composed of a mechanical platform and a control system. It can realize multi-electrode independent micro-energy pulse discharge, real-time detection of each electrode gap state and servo feed adjustment, and synchronous rotation assisted vibration of each electrode. The mechanical platform of the machine tool consists of servo feed mechanism, vibrating mechanism and multi-electrode synchronous rotating mechanism. The structure optimization and stability analysis are carried out by ANSYS finite element analysis software to ensure that the design of each part of the machine tool is reasonable and reliable. The control system is composed of motor control module, servo motion control module and pulse power module. It uses STM32F103RCT6 MCU to detect the machining state in real time and coordinate the work of each module, and uploading the processing data to upper computer. The Experimental tests show that the machine tool has high machining efficiency, stability and precision, and high degree of automation.

Simulation and Optimization Design of CRH380A EMU Bogie Frame

Taking SKMB-200 power bogie frame applied to CRH380A EMU as the research object, based on UIC615-4 standard, four kinds of simulated operating conditions load and one kind of supernormal load are calculated, and then constraints and loads required for ABAQUS simulation analysis are determined. The results of static strength simulation show that the maximum stress of the frame under simulated operation conditions, and under abnormal load conditions are lower than the allowable stress of the main material SMA490BW weathering steel. The static strength of the frame meets the standard. Then, through setting design variables, selecting constraints and determining the objective function, the structural optimization analysis of the selected abnormal load cases is carried out. The optimization results show that the total mass is reduced by 109 kg, which is 6.8% lower than that before optimization, and the maximum equivalent stress value of the frame is 329.98 MPa, which still meets the strength requirements. By optimizing the structural parameters of the frame, the under-spring mass of SKMB-200 bogie can be effectively reduced, and its dynamic performance can be improved, which can provide reference for the optimum design of the bogie structure of EMU.

Structural Optimization and Heat Transfer Performance Analysis of a Cone-Column Combined Heat Sink

Abstract To address the impact of temperature on the normal operation and service life of high-power electronic components, a circular microchannel heat sink with cones has been designed. The cones are evenly arranged inside circular microchannels, which can change the flow state of the cooling medium in the microchannels and enhance the heat transfer performance. The experimental scheme of the heat transfer performance of microchannel heat sink was designed by an orthogonal test method, and the numerical simulation was carried out by ansys thermal-fluid–solid coupling. Within the test parameters, the inlet pore size, the split outer diameter, and the number of cone columns have effect the temperature of the heat sink base. Further, the inlet pore size and the number of cone columns have a heightened effect on the test results: the base temperature of the heat sink decreases rapidly with the increase in the inlet pore size and the number of cone columns. According to the orthogonal test analysis, the structural parameters of the heat sink were optimized. Under the condition that the other boundary conditions are the same, the temperature of the heat sink substrate obtained by the new factor levels combination is 27.87 °C.

Structure optimization and thermal field analysis of biogas derived methane fueled Solid Oxide Fuel Cell

The suitability for using various gaseous fuels makes the Solid Oxide Fuel Cell (SOFC) the most promising heat-electricity cogeneration device. Thermal field distribution of SOFC directly determines whether the cell is operating in sufficient catalytic activity and weakened by thermal stress. For biogas derived methane fueled SOFC, the internal reforming reactions can cause the inhomogeneous temperature distribution. So it is crucial to optimize the thermal field to achieve optimal cell operation state. In this paper, a 3D muti-physics model is developed to study the improvements of a new cathode flow field structure. When adopting new cathode structure, the power density increases by over 11%, and the maximum temperature gradient can be evidently reduced.

A direct topological reanalysis algorithm based on updating matrix triangular factorization

Purpose The purpose of this paper is to establish and implement a direct topological reanalysis algorithm for general successive structural modifications, based on the updating matrix triangular factorization (UMTF) method for non-topological modification proposed by Song et al. [Computers and Structures, 143(2014):60-72]. Design/methodology/approach In this method, topological modifications are viewed as a union of symbolic and numerical change of structural matrices. The numerical part is dealt with UMTF by directly updating the matrix triangular factors. For symbolic change, an integral structure which consists of all potential nodes/elements is introduced to avoid side effects on the efficiency during successive modifications. Necessary pre- and post processing are also developed for memory-economic matrix manipulation. Findings The new reanalysis algorithm is applicable to successive general structural modifications for arbitrary modification amplitudes and locations. It explicitly updates the factor matrices of the modified structure and thus guarantees the accuracy as full direct analysis while greatly enhancing the efficiency. Practical implications Examples including evolutionary structural optimization and sequential construction analysis show the capability and efficiency of the algorithm. Originality/value This innovative paper makes direct topological reanalysis be applicable for successive structural modifications in many different areas.

デブロモアプリシアトキシン単純化アナログ・aplog-1の構造最適化ならびにがん細胞増殖抑制機構の解析

デブロモアプリシアトキシン単純化アナログ・aplog-1の構造最適化ならびにがん細胞増殖抑制機構の解析

Structural Optimization and Reliability Analysis of Automotive Composite Bumper Against Low-Velocity Longitudinal and Corner Pendulum Impacts

To improve the safety performance and maintain light weight of composite automotive bumper beams subjected to low-velocity impacts, a structural optimization and a novel reliability analysis procedure for multi-objectives are established in this paper. Both longitudinal and corner pendulum impacts are considered, and the optimized bumper beam has significant improvements. Compared with the original composite bumper beam, the section force of the crash box in the corner pendulum impact and the mass of the optimal bumper beam are decreased by 9.6% and 20.3%, respectively. The novel reliability analysis results show that the knee point may be less reliable whereas the design with inferior knee point is of higher reliability. Therefore, a design on an inferior knee point may be more attractive in engineering design practices. Our numerical results have demonstrated that the optimization procedure established in this paper to improve the performance of composite bumper beams and our proposed reliability analysis method considering multi-objectives are effective and useful in the engineering design of bumper beams. These techniques are also useful for the design of other types of structural components where weight and safety are of importance.

Multi-objective Dimensional Optimization of a 3-DOF Translational PKM Considering Transmission Properties

Multi-objective dimensional optimization of parallel kinematic manipulators (PKMs) remains a challenging and worthwhile research endeavor. This paper presents a straightforward and systematic methodology for implementing the structure optimization analysis of a 3-prismatic-universal-universal (PUU) PKM when simultaneously considering motion transmission, velocity transmission and acceleration transmission. Firstly, inspired by a planar four-bar linkage mechanism, the motion transmission index of the spatial parallel manipulator is based on transmission angle which is defined as the pressure angle amongst limbs. Then, the velocity transmission index and acceleration transmission index are derived through the corresponding kinematics model. The multi-objective dimensional optimization under specific constraints is carried out by the improved non-dominated sorting genetic algorithm (NSGA II), resulting in a set of Pareto optimal solutions. The final chosen solution shows that the manipulator with the optimized structure parameters can provide excellent motion, velocity and acceleration transmission properties.

Design optimization of a diesel engine connecting rod

Rotary motion is generated from a crankshaft’s piston alternating motion using a connecting rod. The engine combustion gases and components motion of inertia exert pressures that induces compressive and tensile stress in the connecting rod respectively [1], [2]. Connecting rods fail due to its overloading, bearing failure, irregular adjustments of the bolts and faulty assembly or fatigue [3]. It is important for connecting rods to be able to withstand the complex high tensile loads that acts on them. As a result, numerous design technology, material selection, working and fatigue test of a connecting rod have been studied and presented [4]. Mechanical properties (such as hardness, tensile strength, rigidity and fatigue resistivity) of the materials used in the manufacture of a connecting rod need vehicles depends on the design of the connecting rod. Failure of connecting rod is attributed to the in availability of much strength needed to hold the load. This can be overcome with the life cycle extended by increasing the strength [5].
 Finite element analysis of connecting rod have been conducted and presented by a lot of researchers. In [6], theoretical and FEA of an IC engine connecting rod was conducted. The result of the analysis obtained shows the causes of failure at the fillet of both ends due to the induced stress. In [7] static FEA for fatigue, deformation and weight optimization of a connecting rod using ANSYS workbench is carried out and presented. From the suggested design changes obtained from the weight optimization result, the failure result is further updated to achieve a better result. In a paper by Bansal, dynamic stress analysis was carried out on a single cylinder four stroke diesel engine connecting rod of Aluminum material using FEA. The optimization was also done under dynamic loading with the boundary conditions and inputs determined from the pressure-volume diagram and engine specification chart respectively are carried out with different meshing size for an accurate result. [8].
 FEA is the commonly employed computational tool for testing and modifying engineering structures within certain design limit. It involves diving in to small units known as ‘elements’ for static and dynamic analysis of simple to complex model under different design constraints. Further investigation can also be done to improve the design for optimal performance and lifespan with regards to design failure [9].
 Many kinds of literature have worked on weight optimization. Gaikwad in his paper modifies a roller conveyor by performing weight optimization after carrying out static analysis on the roller conveyor [10] In another paper by [10] the weight of a roller conveyor was reduced thereby saving the materials under specific load constraints using finite element method.
 In this paper shape optimization with target weight reduction rate of 20 to 60% with an interval of 10 under a static loading of 100N. Further analysis for structural optimization is also done to determine a new optimized structure with new deformation and stress values respectively. The analysis is carried out in ANSYS static structural, mechanical solver with a tensile force of 100N acting on its larger end.