scholarly journals Structural Optimization Design of Ship Lock Heads on Soft Soil considering Time-Varying Effects of the Structure and Foundation

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Jiawei Bai ◽  
Chao Su ◽  
Heng Zhang ◽  
Shaopei Hu
Keyword(s):  
Structural Optimization ◽  
Optimization Design ◽  
Soft Soil ◽  
Optimization Procedure ◽  
Optimized Design ◽  
Time Varying ◽  
The Maximum Principle ◽  
Hybrid Particle Swarm Optimization ◽  
Whale Optimization ◽  
Ship Lock

Over time, the uneven settlements of the structure and foundation are prominent in constructing ship lock heads on soft soil. These deformations endanger the safety of ship lock heads during construction. This research aimed to establish the ship lock head’s structural optimization procedure on soft soil, considering the time-varying effects of the structure and foundation. By comprehensively considering the linear viscoelastic creep of concrete and the elastoplastic consolidation characteristic of soft soil, a perfect time-dependent analysis method for the lock head on soft soil was proposed. Furthermore, a hybrid particle swarm optimization, enhanced whale optimization, and differential evolution (PSO-EWOA-DE) algorithm was proposed to optimize thirty-four design variables of a lock head. With the minimal volume of the lock head as the optimization objective, the finite element model was established. In the optimization process, three types of constraints were evaluated. The result showed that the optimized design could reduce 10.45% of structure volume. Through comparing and analysing the maximum principle stresses and vertical displacements of the lock head before and after optimization, some conclusions were drawn. The optimization procedure proposed in this paper provides a new perspective for the structural optimization of hydraulic structures on soft soil.

A structural optimization design for an aluminum-intensive vehicle

2003 ◽  
Vol 217 (9) ◽  
pp. 771-779 ◽  
Author(s):  
Dong-Chan Lee ◽  
Jeong-Ick Lee
Keyword(s):  
Structural Optimization ◽  
Optimization Design ◽  
Joint Stiffness ◽  
Optimization Procedure ◽  
Steel Structure ◽  
Torsional Stiffness ◽  
Production Parameter ◽  
Parameter Region ◽  
Vehicle Structure ◽  
Structural Responses

This paper describes an integrated structural optimization procedure using a multilevel decomposition technique and a domain mapping contour that can represent the production parameter region. At the upper level, the structural responses are represented in terms of global quantities, i.e. stiffness, stresses and weight. At the lower level, the structural responses are represented in terms of local quantities, i.e. the intermediate parameters or the detailed dimensions based on the production parameter region. This technique was applied to develop the aluminium vehicle structure. The crosssectional characteristics and joint stiffness of the vehicle structure are calculated from the vehicle structure model which is composed of shell-beam-spring elements. In comparison with the base model (steel structure), the bending stiffness and torsional stiffness of the developed aluminium vehicle structure increase by around 45 and 35 per cent respectively, and the weight reduction is around 30 per cent. The manufactured structure is also presented.

scholarly journals Parametric Design and Optimization of the Profile of Autonomous Underwater Helicopter Based on NURBS

2021 ◽  
Vol 9 (6) ◽  
pp. 668
Author(s):  
Xinyu An ◽  
Ying Chen ◽  
Haocai Huang
Keyword(s):  
Optimization Design ◽  
Cfd Simulation ◽  
Autonomous Underwater Vehicle ◽  
Optimization Procedure ◽  
Parametric Representation ◽  
Hydrodynamic Performance ◽  
Optimized Design ◽  
Parametric Curve ◽  
Design Variables ◽  
Drag Ratio

Autonomous Underwater Helicopter (AUH) is a disk-shaped Autonomous Underwater Vehicle (AUV), and it has comparative advantage of near-bottom hovering and whole-direction turn-around ability over the traditional slender AUV. An optimization design of its irregular geometric profile is essential to improve its hydrodynamic performance. A parametric representation of its profile is proposed in this paper using Non-Uniform Rational B-spline (NURBS) curve. The parametric representation of AUH profile is described with two decision variables and several data points. Based on this parametric curve, Computational Fluid Dynamics (CFD) simulation is carried out to evaluate its hydrodynamic performance with various parameters. A predication model is established over variables’ design space using Kriging surrogate model with CFD simulation results and a Genetic Algorithm (GA) procedure is conducted to find optimal design variables, which can produce an optimum lift-drag ratio. CFD verification results confirm that AUH profile with optimized design variables can increase its lift-drag ratio by 2.11 times compared with that of non-optimized ones. It demonstrates that the parametric representation and optimization procedure of AUH profile proposed in this paper is feasible, and it has a great potential in improving AUH’s performance.

Optimization Research on Dynamic Balance of Spatial Engine under Limiting Shaking Moment

2009 ◽  
Vol 626-627 ◽  
pp. 693-698
Author(s):  
Yong Yong Zhu ◽  
S.Y. Gao
Keyword(s):  
Mathematical Model ◽  
Objective Function ◽  
Kinetic Analysis ◽  
Optimization Design ◽  
Design Method ◽  
Dynamic Balance ◽  
Optimized Design ◽  
Design Variables ◽  
The Mathematical Model ◽  
Shaking Moment

Dynamic balance of the spatial engine is researched. By considering the special wobble-plate engine as the model of spatial RRSSC linkages, design variables on the engine structure are confirmed based on the configuration characters and kinetic analysis of wobble-plate engine. In order to control the vibration of the engine frame and to decrease noise caused by the spatial engine, objective function is choosed as the dimensionless combinations of the various shaking forces and moments, the restriction condition of which presents limiting the percent of shaking moment. Then the optimization design is investigated by the mathematical model for dynamic balance. By use of the optimization design method to a type of wobble-plate engine, the optimization process as an example is demonstrated, it shows that the optimized design method benefits to control vibration and noise on the engines and improve the performance practically and theoretically.

Structural Optimization of Composite Panel with Lamination Parameters and Equivalent Stiffness Laminate Method

2014 ◽  
Vol 496-500 ◽  
pp. 429-435
Author(s):  
Xiao Ping Zhong ◽  
Peng Jin
Keyword(s):  
Genetic Algorithm ◽  
Structural Optimization ◽  
Composite Structure ◽  
Optimization Procedure ◽  
Optimization Method ◽  
Composite Panel ◽  
Analysis Tool ◽  
Equivalent Stiffness ◽  
Lamination Parameters ◽  
Design Variables

Firstly, a two-level optimization procedure for composite structure is investigated with lamination parameters as design variables and MSC.Nastran as analysis tool. The details using lamination parameters as MSC.Nastran input parameters are presented. Secondly, with a proper equivalent stiffness laminate built to substitute for the lamination parameters, a two-level optimization method based on the equivalent stiffness laminate is proposed. Compared with the lamination parameters-based method, the layer thicknesses of the equivalent stiffness laminate are adopted as continuous design variables at the first level. The corresponding lamination parameters are calculated from the optimal layer thicknesses. At the second level, genetic algorithm (GA) is applied to identify an optimal laminate configuration to target the lamination parameters obtained. The numerical example shows that the proposed method without considering constraints of lamination parameters can obtain better optimal results.

scholarly journals Structure Optimization of UHV RIP Oil-SF6 bushings Based on Improved Equal Margin Design Method and Back-Propagation Neural Network

2021 ◽  
Vol 261 ◽  
pp. 03040
Author(s):  
Zhang Shiling
Keyword(s):  
Field Distribution ◽  
Optimization Design ◽  
Design Method ◽  
Back Propagation ◽  
Back Propagation Neural Network ◽  
Analytic Formula ◽  
Optimized Design ◽  
Thermal Coupling ◽  
Coupling Calculation ◽  
Temperature Factors

Equal margin design method based on the classic analytic formula is widely used in development of extra-high voltage bushing products, and its effectiveness and practicality have been fully validated. However, model and temperature factors have significant impact on internal E-field distribution of UHVAC and UHVDC bushing condenser, which traditional analytic formula is difficult to evaluate quantitatively, so it’s necessary to improve traditional equal margin design method. Firstly, basic principles of equal margin design method and its software package were briefly described, and the laws of model and temperature factors influencing on condenser E-field were investigated on FEM (finite element method) computing platform. Based on these, mathematical model of improved equal margin design method for bushing condenser was established, and flow chart of optimization process combining FEM electro-thermal coupling calculation with genetic algorithm was presented. The improved method was applied to design of UHV RIP oil-gas prototype to realize uniform axial E-field distribution along bushing condenser and equal partial discharge margin between adjacent foils. Bushing condenser was fabricated according to above optimized design structure, and has passed all type tests. In the paper, the FEM electro-thermal coupling calculation method was applied to the inner insulation optimization design to make bushing condenser’s design more suitable. The paper can provide some theoretical guidelines for research and development of other bushings in UHV level.

scholarly journals Test signal generation for analog circuits

2003 ◽  
Vol 1 ◽  
pp. 235-238
Author(s):  
B. Burdiek ◽  
W. Mathis
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Analog Circuits ◽  
Variational Calculus ◽  
Optimization Procedure ◽  
Test Signal ◽  
Signal Generation ◽  
Optimal Test ◽  
The Maximum Principle

Abstract. In this paper a new test signal generation approach for general analog circuits based on the variational calculus and modern control theory methods is presented. The computed transient test signals also called test stimuli are optimal with respect to the detection of a given fault set by means of a predefined merit functional representing a fault detection criterion. The test signal generation problem of finding optimal test stimuli detecting all faults form the fault set is formulated as an optimal control problem. The solution of the optimal control problem representing the test stimuli is computed using an optimization procedure. The optimization procedure is based on the necessary conditions for optimality like the maximum principle of Pontryagin and adjoint circuit equations.

A New ERR and Strategy for Bi-Directional Evolutionary Structural Optimization

2012 ◽  
Vol 204-208 ◽  
pp. 4422-4428
Author(s):  
Da Ke Zhang ◽  
Wen Pan Zhang ◽  
Han He ◽  
Chong Wang
Keyword(s):  
Structural Optimization ◽  
Stress Level ◽  
Optimization Procedure ◽  
Optimal Process ◽  
Removal Ratio ◽  
Rejection Ratio ◽  
Evolutionary Structural Optimization ◽  
Rejection Criterion ◽  
Element Addition ◽  
Element Removal

The efficiency of the element removal or addition is of significance for evolutionary structural optimization (ESO) process. The key is to find an appropriate rejection criterion (RC) which allows to assess the contribution of each element to the specified behavior（stress, stiffness, displacement, etc.）of the structure, and to subsequently remove elements with least contribution. This paper proposed a varying elements removal ratio (VERR) method which uses a larger ERR (Element Rejection Ratio) value at early iterations where exist a lot of redundant material, and decreases the value of ERR in the optimal process to lessen the number of elements removed at later iterations. Meanwhile, this paper proposed a strategy for element addition based on stress level and the contribution of elements to the structure in order to decide which elements should be added to the model and the sequence of the element addition. With the proposed VERR and the strategy, the optimization procedure of the structure evolves more quickly and smoothly.

Structural Optimization Design of an Aircraft Metal-Composite Wing

2013 ◽  
Vol 341-342 ◽  
pp. 519-523
Author(s):  
Ya Hui Zhang ◽  
Ji Hong Zhu ◽  
Jun Shuo Li ◽  
Wei Hong Zhang
Keyword(s):  
Structural Optimization ◽  
Optimization Design ◽  
Optimization Method ◽  
Design Solution ◽  
Metal Composite ◽  
Concept Design ◽  
Obvious Effect ◽  
Reinforced Composite ◽  
Three Phase ◽  
Composite Wing

The problem of metal-composite wing structural optimization is discussed and a strategy is presented. Topology optimization method is applied to provide load transferring path of structure for concept design. Size, shape and other optimization method are used to provide detailed design for individual components. A three-phase optimization method is discussed for fiber reinforced composite laminate skin. Optimal parameters include ply angle, percentage, thickness, layer shape and sequence. The design of laminate for ease of manufacture is based on a set of manufacturing constraints. This paper deals with a total optimal design solution for aileron structure of an aircraft. The result satisfies all the requirements of strength and stability, and has obvious effect of weight loss.

Structural optimization design for antenna bracket manufactured by selective laser melting

2018 ◽  
Vol 24 (3) ◽  
pp. 539-547 ◽  
Author(s):  
Zefeng Xiao ◽  
Yongqiang Yang ◽  
Di Wang ◽  
Changhui Song ◽  
Yuchao Bai
Keyword(s):  
Structural Optimization ◽  
Modal Analysis ◽  
Selective Laser Melting ◽  
Optimization Model ◽  
Optimization Design ◽  
Analysis Data ◽  
Laser Melting ◽  
Design Rules ◽  
Content Type ◽  
Process Characteristics

Purpose This paper aims to summarize design rules based on the process characteristics of selective laser melting (SLM) and structural optimization and apply the design rules in the lightweight design of an aluminum alloy antenna bracket. The design goal is to reduce 30 per cent of the weight while maintaining the stress levels in the original part. Design/methodology/approach To reduce weight as much as possible, the titanium alloy with higher specific strength was selected during the process of optimization. The material distribution of the bracket was improved by the topology optimization design. The redesign for SLM was used to obtain an optimization model, which was more suitable for SLM. The component performance was improved by shape optimization. The modal analysis data of the structural optimization model were compared with those of the stochastic lightweight model to verify the structural optimization model. The scanning data were compared with those of the original model to verify whether the model was suitable for SLM. Findings Structural optimization design for antenna bracket realized the mass decrease of 30.43 per cent and the fundamental frequency increase of 50.18 per cent. The modal analysis data of the stochastic lightweight model and the structural optimization model indicated that the optimization performance of structural optimization method was better than that of the stochastic lightweight method. The comparison results between the scanning data of the forming part and the original data confirmed that the structural optimization design for SLM lightweight component could achieve the desired forming accuracy. Originality/value This paper summarizes geometric constraints in SLM and derives design rules of structural optimization based on the process characteristics of SLM. SLM design rules make structural optimization design more reasonable. The combination of structural optimization design and SLM can improve the performance of lightweight antenna bracket significantly.

A Probabilistic Tolerance Allocation Method for Dynamic Mechanical Systems With Periodic Response and Discontinuous Forcing Functions

1995 ◽  
Author(s):  
F. Zhang ◽  
B. J. Gilmore ◽  
A. Sinha
Keyword(s):  
Combustion Engine ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Optimization Procedure ◽  
Tolerance Allocation ◽  
Radial Clearance ◽  
Time Varying ◽  
Link Length ◽  
Design Variables ◽  
Forcing Functions

Abstract Tolerance allocation standards do not exist for mechanical systems whose response are time varying and are subjected to discontinuous forcing functions. Previous approaches based on optimization and numerical integration of the dynamic equations of motion encounter difficulty with determining sensitivities around the force discontinuity. The Alternating Frequency/Time approach is applied here to capture the effect of the discontinuity. The effective link length model is used to model the system and to account for the uncertainties in the link length, radial clearance and pin location. Since the effective link length model is applied, the equations of motion for the nominal system can be applied for the entire analysis. Optimization procedure is applied to the problem where the objective is to minimize the manufacturing costs and satisfy the constraints imposed on mechanical errors and design variables. Examples of tolerance allocation are presented for a single cylinder internal combustion engine.

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