Optimal design of aerospace structures using recent meta-heuristic algorithms

2021 ◽  
Vol 63 (11) ◽  
pp. 1025-1031
Author(s):  
Faik Fatih Korkmaz ◽  
Mert Subran ◽  
Ali Rıza Yıldız
Keyword(s):  
Heuristic Algorithms ◽  
Optimal Solution ◽  
Von Mises Stress ◽  
Grey Wolf Optimizer ◽  
Local Optima ◽  
Design And Optimization ◽  
Shape Perturbation ◽  
Novel Algorithms ◽  
Von Mises ◽  
Conventional Optimization

Abstract Most conventional optimization approaches are deterministic and based on the derivative information of a problem’s function. On the other hand, nature-inspired and evolution-based algorithms have a stochastic method for finding the optimal solution. They have become a more popular design and optimization tool, with a continually growing development of novel algorithms and new applications. Flexibility, easy implementation, and the capability to avoid local optima are significant advantages of these algorithms. In this study, shapes, and shape perturbation limits of a bracket part, which is used in aviation, have been set using the hypermorph tool. The objective function of the optimization problem is minimizing the volume, and the constraint is maximum von Mises stress on the structure. The grey wolf optimizer (GWO) and the moth-flame Optimizer (MFO) have been selected as nature-inspired evolution-based optimizers.

scholarly journals Design and Fatigue Optimization of Drive Shaft

2021 ◽  
Vol 9 (VIII) ◽  
pp. 194-203
Author(s):  
Ashish Bawkar
Keyword(s):  
Fatigue Life ◽  
Natural Frequency ◽  
Drive Shaft ◽  
Von Mises Stress ◽  
Hollow Shaft ◽  
Design And Optimization ◽  
The Road ◽  
Increasing Demand ◽  
Von Mises ◽  
Fea Analysis

This work aims towards the design and optimization of the drive shaft as there is increasing demand for weight reduction in an automobile vehicle. The drive shaft is basically a torque transmitting element which transmit the torque from the differential gearbox to the respective wheels. In general, the drive shafts are subjected to fluctuating loads as the torque requirement changes according to the road conditions. Due to this, the drive shaft should be designed considering fatigue failure. The Maruti Suzuki Ertiga model is chosen for design and optimization of the drive shaft. For the fatigue life predicting of the drive shaft, the S-N curve approach is used. Furthermore, the inner diameter of the shaft is varied to obtain the optimized diameter of a hollow shaft which can withstand these fluctuating loads without failure. Along with fatigue life prediction, the natural frequency of the hollow shaft is also calculated. Furthermore, the parametric analysis is carried out of fatigue FOS, Von mises stress, weight and natural frequency of the shaft by varying the diameter ratio of the hollow shaft, and the nature of variation of these parameters are plotted in their respective graphs. The design is validated by performing FEA analysis for each case of a hollow shaft using Ansys software. Finally, from the FEA analysis we conclude that the optimized dimensions of the hollow drive shaft are safe.

scholarly journals Optimization of Fuzzy Logic Controller by Using Heuristic Algorithms

2019 ◽  
pp. 13-18
Author(s):  
Sinan Unsal ◽  
Ibrahim Aliskan
Keyword(s):  
Fuzzy Logic ◽  
Systematic Approach ◽  
Fuzzy Logic Controller ◽  
Heuristic Algorithms ◽  
Algorithm Design ◽  
Optimal Solution ◽  
Design Parameters ◽  
Fuzzy Logic Controllers ◽  
Swarm Optimization ◽  
Design And Optimization

There are many design parameters in the structure of fuzzy logic controllers. Conventional methods that don't have a systematic approach are often used in determining of these parameters. However, setting the controller parameters in this way leads to long experiments and this takes a lot of time. For this reason, design parameters of the fuzzy logic controller are usually determined by using heuristic algorithms. Because, heuristic algorithms can offer solutions that are very close to the optimal solution for the problems where exact solution cannot be obtained. In this study, output membership functions of a fuzzy logic controller are optimized using particle swarm optimization and genetic algorithm. Design and optimization stages are explained in detail and results are compared with each other.

Finite Element Analysis of an Electro-Mechanical Knee Loading Device

2016 ◽  
Author(s):  
Sai Krishna Prabhala ◽  
Sohel Anwar ◽  
Hiroki Yokota ◽  
Stanley Chien
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Human Subjects ◽  
Optimal Solution ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Knee Loading ◽  
Key Factor ◽  
Von Mises ◽  
Fea Analysis

The mechanical loading of knee is an effective regimen for treatment of bone related ailments like fractures, osteoarthritis, and osteoporosis [1–2]. Efficacy of knee loading is evident from the previous studies done on rodents and other small animals [3]. In order to test this loading concept on human subjects, a prototype of a portable and compact device was designed previously. In this study, the prototype device was re-designed with a modified slider crank mechanism. Since this device has multiple moving parts, durability of the parts under stress is a key factor for its success. Thus, this paper focuses on its mechanical characteristics using finite element analysis (FEA). In particular, structural deformities and modal frequency characteristics are analyzed. The FEA analysis is performed on a CAD model of the device. The static structural and modal analyses are performed on two different configurations, in which different materials were used for selected components. Individual parts were meshed and solved extensively to obtain useful results under maximum loading conditions, such as total deformation, Von Mises stress, and modal frequencies. The analysis results show that ABS plastic based design provides an optimal solution in terms weight, cost, and usability.

Design and Optimization of a Bend-and-Sweep Compliant Mechanism

2013 ◽  
Author(s):  
Yashwanth Tummala ◽  
Mary Frecker ◽  
Aimy Wissa ◽  
James E. Hubbard
Keyword(s):  
Optimization Problem ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Leading Edge ◽  
Von Mises Stress ◽  
Nsga Ii ◽  
Design And Optimization ◽  
Compliant Joint ◽  
Von Mises ◽  
Wing Morphing

A novel contact aided compliant mechanism called a bend-and-sweep compliant mechanism is presented. This mechanism has tailorable nonlinear stiffness properties in two orthogonal directions. The fundamental element of this compliant mechanism is the Angled Compliant Joint (ACJ), and the geometric parameters determine the stiffness. This paper presents the design and optimization of such a compliant mechanism. A multi-objective optimization problem was formulated for design optimization of the bend-and-sweep compliant mechanism. The objectives of the optimization problem were to maximize the bending and sweep displacements while minimizing the von Mises stress and mass of each mechanism. This optimization problem was solved using NSGA-II (a genetic algorithm). The results of this optimization for a single ACJ during upstroke and downstroke are presented. Results of two different loading conditions used during optimization of a single ACJ for upstroke are presented. Finally, optimization results comparing the performance of compliant mechanisms with one and two ACJs are also presented. It can be inferred from these results that the number of ACJs and the design of each ACJ determines the stiffness of the bend-and-sweep compliant mechanism. These mechanisms can be used in various applications. Ornithopters or flapping wing unmanned aerial vehicles have unique potential to revolutionize both civil and military applications. The overall goal of this research is to improve the performance of such ornithopters by passively morphing their wings. Passive wing morphing of ornithopters can be achieved by inserting contact-aided compliant mechanisms in the leading edge wing spar. Previously the authors have shown that bending of ornithopter wings can be achieved by integrating a one degree of freedom contact aided compliant mechanism called a compliant spine. The spine was inserted into the leading edge spar and successful flight testing has shown that passive wing bending in ornithopters is feasible and results in significant improvements in lift and thrust. In order to achieve a bio-inspired wing gait called continuous vortex gait, the wings of the ornithopter need to bend, sweep, and twist simultaneously. This can be achieved by using the bend-and-sweep compliant presented in this paper.

scholarly journals Personnel Scheduling Problem under Hierarchical Management Based on Intelligent Algorithm

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Li Huang ◽  
Chunming Ye ◽  
Jie Gao ◽  
Po-Chou Shih ◽  
Franley Mngumi ◽  
...  
Keyword(s):  
Heuristic Algorithms ◽  
Optimal Solution ◽  
Grey Wolf Optimizer ◽  
Scheduling Problem ◽  
Nurse Scheduling ◽  
Intelligent Algorithm ◽  
Charge Nurses ◽  
Hierarchical Management ◽  
Two Hybrid ◽  
Better Than

This paper studies a special scheduling problem under hierarchical management in nurse staff. This is a more complex rostering problem than traditional nurse scheduling. The first is that the rostering requirements of charge nurses and general nurses are different under hierarchical management. The second is that nurses are preferable for relative fair rather than absolute fair under hierarchical management. The model aims at allocating the required workload to meet the operational requirements, weekend rostering preferences, and relative fairness preferences. Two hybrid heuristic algorithms based on multiobjective grey wolf optimizer (MOGWO) and three corresponding single heuristic algorithms are employed to solve this problem. The experimental results based on real cases from the Third People’s Hospital, Panzhihua, China, show that MOGWO does not as good as it does on other engineering optimization. However, the hybrid algorithms based on MOGWO are better than corresponding single algorithms on generational distance (GD) and spacing (SP) of Pareto solutions. Furthermore, for relative fair rostering objective, NSGAII-MOGWO has more power to find the optimal solution in the dimension of relative fairness.

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

The Influence of Loading Position in A Priori High Stress Detection using Mode Superposition

2020 ◽  
Vol 1 (1) ◽  
pp. 93-102
Author(s):  
Carsten Strzalka ◽  
◽  
Manfred Zehn ◽  
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
A Priori ◽  
High Stress ◽  
Von Mises Stress ◽  
Detailed Knowledge ◽  
Variable Loading ◽  
Numerical Effort ◽  
Von Mises

For the analysis of structural components, the finite element method (FEM) has become the most widely applied tool for numerical stress- and subsequent durability analyses. In industrial application advanced FE-models result in high numbers of degrees of freedom, making dynamic analyses time-consuming and expensive. As detailed finite element models are necessary for accurate stress results, the resulting data and connected numerical effort from dynamic stress analysis can be high. For the reduction of that effort, sophisticated methods have been developed to limit numerical calculations and processing of data to only small fractions of the global model. Therefore, detailed knowledge of the position of a component’s highly stressed areas is of great advantage for any present or subsequent analysis steps. In this paper an efficient method for the a priori detection of highly stressed areas of force-excited components is presented, based on modal stress superposition. As the component’s dynamic response and corresponding stress is always a function of its excitation, special attention is paid to the influence of the loading position. Based on the frequency domain solution of the modally decoupled equations of motion, a coefficient for a priori weighted superposition of modal von Mises stress fields is developed and validated on a simply supported cantilever beam structure with variable loading positions. The proposed approach is then applied to a simplified industrial model of a twist beam rear axle.

scholarly journals Numerical Investigation of the Deformable Porous Media Treated by the Intermittent Microwave

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 757
Author(s):  
Tianyi Su ◽  
Wenqing Zhang ◽  
Zhijun Zhang ◽  
Xiaowei Wang ◽  
Shiwei Zhang
Keyword(s):  
Porous Media ◽  
Heat Transport ◽  
Liquid Water ◽  
Von Mises Stress ◽  
Temperature Deformation ◽  
Local Maxima ◽  
Whole Process ◽  
Surface Areas ◽  
Pulse Ratio ◽  
Von Mises

A 2D axi-symmetric theoretical model of dielectric porous media in intermittent microwave (IMW) thermal process was developed, and the electromagnetic energy, multiphase transport, phase change, large deformation, and glass transition were taken into consideration. From the simulation results, the mass was mainly carried by the liquid water, and the heat was mainly carried by liquid water and solid. The diffusion was the dominant mechanism of the mass transport during the whole process, whereas for the heat transport, the convection dominated the heat transport near the surface areas during the heating stage. The von Mises stress reached local maxima at different locations at different stages, and all were lower than the fracture stress. A material treated by a longer intermittent cycle length with the same pulse ratio (PR) tended to trigger the phenomena of overheat and fracture due to the more intense fluctuation of moisture content, temperature, deformation, and von Mises stress. The model can be extended to simulate the intermittent radio frequency (IRF) process on the basis of which one can select a suitable energy source for a specific process.

scholarly journals Finite Element Analysis of Composite Repair for Damaged Steel Pipeline

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 301
Author(s):  
Jiaqi Chen ◽  
Hao Wang ◽  
Milad Salemi ◽  
Perumalsamy N. Balaguru
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Hoop Stress ◽  
Pipe Wall ◽  
Von Mises Stress ◽  
Repair System ◽  
Composite Repair ◽  
Steel Pipeline ◽  
Von Mises ◽  
Infill Material

Carbon fiber reinforced polymer (CFRP) matrix composite overwrap repair systems have been introduced and accepted as an alternative repair system for steel pipeline. This paper aimed to evaluate the mechanical behavior of damaged steel pipeline with CFRP repair using finite element (FE) analysis. Two different repair strategies, namely wrap repair and patch repair, were considered. The mechanical responses of pipeline with the composite repair system under the maximum allowable operating pressure (MAOP) was analyzed using the validated FE models. The design parameters of the CFRP repair system were analyzed, including patch/wrap size and thickness, defect size, interface bonding, and the material properties of the infill material. The results show that both the stress in the pipe wall and CFRP could be reduced by using a thicker CFRP. With the increase in patch size in the hoop direction, the maximum von Mises stress in the pipe wall generally decreased as the maximum hoop stress in the CFRP increased. The reinforcement of the CFRP repair system could be enhanced by using infill material with a higher elastic modulus. The CFRP patch tended to cause higher interface shear stress than CFRP wrap, but the shear stress could be reduced by using a thicker CFRP. Compared with the fully bonded condition, the frictional interface causes a decrease in hoop stress in the CFRP but an increase in von Mises stress in the steel. The study results indicate the feasibility of composite repair for damaged steel pipeline.

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