Knowledge creation and application of optimal tolerance distribution method for aircraft product assembly

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Md Helal Miah ◽  
Jianhua Zhang ◽  
Dharmahinder Singh Chand
Keyword(s):  
Optimization Method ◽  
Optimization Techniques ◽  
Tolerance Allocation ◽  
Content Type ◽  
Tolerance Optimization ◽  
Assembly Accuracy ◽  
New Equation ◽  
Tolerance Distribution ◽  
The Cost ◽  
Product Assembly

Purpose This paper aims to illustrate the tolerance optimization method based on the assembly accuracy constrain, precession constrain and the cost of production of the assembly product. Design/methodology/approach A tolerance optimization method is an excellent way to perform product assembly performance. The tolerance optimization method is adapted to the process analysis of the hatch and skin of an aircraft. In this paper, the tolerance optimization techniques are applied to the tolerance allocation for step difference analysis (example: step difference between aircraft cabin door and fuselage outer skin). First, a mathematical model is described to understand the relationship between manufacturing cost and tolerance cost. Second, the penalty function method is applied to form a new equation for tolerance optimization. Finally, MATLAB software is used to calculate 170 loops iteration to understand the efficiency of the new equation for tolerance optimization. Findings The tolerance optimization method is based on the assembly accuracy constrain, machinery constrain and the cost of production of the assembly product. The main finding of this paper is the lowest assembly and lowest production costs that met the product tolerance specification. Research limitations/implications This paper illustrated an efficient method of tolerance allocation for products assembly. After 170 loops iterations, it founds that the results very close to the original required tolerance. But it can easily say that the different number of loops iterations may have a different result. But optimization result must be approximate to the original tolerance requirements. Practical implications It is evident from Table 4 that the tolerance of the closed loop is 1.3999 after the tolerance distribution is completed, which is less than and very close to the original tolerance of 1.40; the machining precision constraint of the outer skin of the cabin door and the fuselage is satisfied, and the assembly precision constraint of the closed loop is satisfied. Originality/value The research may support further research studies to minimize cost tolerance allocation using tolerance cost optimization techniques, which must meet the given constrain accuracy for assembly products.

Optimization of Multistage Machining Systems, Part 1: Mathematical Solution

1992 ◽  
Vol 114 (4) ◽  
pp. 524-531 ◽  
Author(s):  
J. S. Agapiou
Keyword(s):  
Optimization Problem ◽  
Cutting Parameters ◽  
Optimization Method ◽  
Idle Time ◽  
Optimization Techniques ◽  
Machining Parameters ◽  
Machining Time ◽  
Physical Constraints ◽  
Time Requirements ◽  
The Cost

The optimization problem for multistage machining systems has been investigated. Due to uneven time requirements at different stages in manufacturing, there could be idle times at various stations. It may be advantageous to reduce the values of machining parameters in order to reduce the cost at stations that require less machining time. However, optimization techniques available through the literature do not effectively utilize the idle time for the different stations generated during the balancing of the system. Proposed in this paper is an optimization method which utilizes the idle time to the full extent at all machining stations, with the intention of improving tool life and thus achieving cost reduction. The mathematical analysis considers the optimization of the production cost with an equality constraint of zero idle time for the stations with idle time. Physical constraints regarding the cutting parameters, force, power, surface finish, etc., as they arise in different operations, are also considered. The aforementioned problem has been theoretically analyzed and a computational algorithm developed. The advantages and effectiveness of the proposed approach are finally established through an example.

scholarly journals Tolerance analysis and optimization based on 3DCS

2021 ◽  
Vol 2137 (1) ◽  
pp. 012070
Author(s):  
Yuan Gao
Keyword(s):  
Three Dimensional ◽  
Tolerance Analysis ◽  
Tolerance Allocation ◽  
Engineering Practice ◽  
Chain Model ◽  
Ring Model ◽  
Assembly Accuracy ◽  
Simulation Results ◽  
Automobile Headlight ◽  
Tolerance Distribution

Abstract At present, with the increasing requirements of major enterprises on assembly accuracy, the problem of interference and excessive clearance between parts needs to be solved. In order to analyze and optimize the tolerances in the actual assembly of the parts, a three-dimensional vector ring model is proposed on the basis of the dimensional chain model, and the tolerance distribution is optimized by the “dichotomy method”. With the help of 3DCS, the virtual assembly of the automobile headlight is carried out, and the sensitivity analysis is carried out by establishing the measurement of the gap between the turn signal and headlight in the automobile headlight, and the simulation results are used to obtain a reasonable improvement in tolerance allocation that meets the design criteria and saves costs. The results are compared with the traditional method of optimizing the allocation of equal tolerances and are clearly superior, providing a method for optimizing the allocation of tolerances to parts in engineering practice.

Forming a TED talks sphere for convenient search

2020 ◽  
Vol 38 (2) ◽  
pp. 403-420
Author(s):  
Chia-Hui Shih ◽  
Han-Lin Li ◽  
Chih-Chien Hu ◽  
Bertrand M.T. Lin
Keyword(s):  
Phase 1 ◽  
Optimization Method ◽  
Optimization Techniques ◽  
Content Type ◽  
Video Systems ◽  
Software And Hardware ◽  
Survey And Evaluation ◽  
Five Phases ◽  
User Friendly ◽  
Ted Talks

Purpose TED (Technology, Entertainment, Design, www.ted.com/) Talks has been one of the most popular video systems. However, the current TED Talks system expressed its inquired videos as in a two-dimensional (2D) table, which is inconvenient for searching the relationships among videos and tags. This study converts the TED Talks table into a sphere by using optimization techniques to help users search for preferred videos. Design/methodology/approach There are five phases in this study as follows. Phase 1: Reorganize data of 36 tags and 108 videos; Phase 2: Allocate tags on the TED sphere; Phase 3: Allocate videos on the TED sphere; Phase 4: Develop an online interactive TED retrieval system; and Phase 5: Perform survey and evaluation. Findings One survey demonstrated that the TED Talks sphere is more convenient for searching videos, as it is more user-friendly because of its graphical user interface, more convenient to use, more useful for retrieving information and can facilitate a more responsive search for users’ preferred videos. Research limitations/implications The numbers of tags and videos able to be displayed on a sphere is limited by the capacity of an optimization software and hardware. Practical implications The proposed sphere system can be used by a large number of users of TED Talks groups. Social implications This sphere systems can also be applied to other fields which use 2D forms to display the relationships among objects. Originality/value This study uses an optimization method to convert a 2D form into a 3D sphere to highlight the relationships among numerous objects.

Simultaneous geometry and cross-section optimization of aluminum trusses

2016 ◽  
Vol 12 (2) ◽  
pp. 315-325
Author(s):  
Moacir Kripka ◽  
Zacarias Chamberlain Pravia ◽  
Guilherme Fleith Medeiros ◽  
Maiga Marques Dias
Keyword(s):  
Cross Section ◽  
Experimental Tests ◽  
Optimization Method ◽  
Optimization Techniques ◽  
Truss Optimization ◽  
Cross Sectional ◽  
Content Type ◽  
Design Variables ◽  
Section Shape ◽  
Nodal Coordinates

Purpose – Trusses constitute a fertile field to demonstrate the application of optimization techniques because of the possibility of several different configurations. Using such techniques allows the search for designs that minimize the use of material to safely comply with the imposed loads. Truss optimization can be classified into three categories: cross-section, shape, and topology. The purpose of this paper is to present a numerical and experimental study developed to minimize the weight of aluminum trusses, taking both the cross-sectional dimensions of the elements and the nodal coordinates as design variables. Design/methodology/approach – Initially, several numerical computer simulations were performed with an optimization program developed by combining the displacement method and a simulated annealing optimization method. Subsequently, two aluminum trusses were selected and built in order to validate the numerical results obtained. Findings – Experimental tests verified the excellent performance of the optimized model. Originality/value – In addition, it was concluded that significant savings could be obtained from the application of the proposed formulation.

Integrated MOORA-ELECTRE approach for solving multi-criteria decision problem

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ranjith R. ◽  
S. Nalin Vimalkumar
Keyword(s):  
Electrical Discharge Machining ◽  
Poor Performance ◽  
Optimization Techniques ◽  
Content Type ◽  
Weight Percentage ◽  
Manufacturing Enterprises ◽  
First Case ◽  
Weight Method ◽  
The Cost ◽  
Selection Of

Purpose The most difficult tasks in the design and development of products for diverse engineering applications were the selection of suitable materials. Choice of inappropriate process variables leads to poor performance, which increases the cost of the product. The selection of the best option of available alternatives is important to improve the performance and productivity of the manufacturing enterprises. Design/methodology/approach The paper aims to develop Hybrid Multi-Criteria Decision Making (HMCDM) by integrating two potential optimization techniques Elimination Et Choix Traduisant la REalité and multi-objective optimization on the basis of ratio analysis. The weight of the criteria was calculated using the critic weight method. Findings The efficiency and flexibility of the proposed HMCDM technique were illustrated and validated by two examples. In the first case, the best electrode material among the five available alternatives was selected for the electrical discharge machining of AZ91/B4Cp magnesium composites. In the second case, the optimum weight percentage of composites providing the best tribological properties was chosen. Originality/value It was noted that the HMCDM methodology was quite simple to comprehend, easy to apply and provided reliable rankings of the material alternatives. The proposed hybrid algorithm is suitable for product optimization as well as design optimization.

Comparison of classic and optimization approach to active power filters sizing and placement

2014 ◽  
Vol 33 (6) ◽  
pp. 1877-1890 ◽  
Author(s):  
Michal Lewandowski ◽  
Janusz Walczak
Keyword(s):  
Power System ◽  
Optimization Method ◽  
Active Power ◽  
Harmonic Compensation ◽  
Content Type ◽  
Active Power Filters ◽  
Power Filters ◽  
Classic Approach ◽  
Simulation Results ◽  
The Cost

Purpose – In most applications the active power filters (APFs) are used to reduce harmonic distortion of a nonlinear load which is located near the APF installation point. This classic approach allows to reduce the distortion introduced to the power system but do not guarantee that the cost of the APFs installation is optimal. The purpose of this paper is to compare the classic approach to harmonic compensation with an optimization method of sizing and placement of the APFs in an existing distributed power network. Design/methodology/approach – An exemplary real-life power system with distributed nonlinear loads was modeled using PCFLO power analysis software. Next, Matlab was used to implement the classic method and the optimization algorithm. Between Matlab and PCFLO a specially written Java middleware was used to provide a seamless workflow integration. Findings – It was shown that the presented optimization method may lead to superior results in comparison with the classic approach. Simulation results clearly showed that the APFs installation cost can be significantly reduced when the optimization algorithm is used. Moreover, the proposed optimization method can overcome some problems connected with the nonlinearity and discontinuity of the APF's price/current function. Research limitations/implications – There are two main limitations of the presented method. First, the method needs much more computing power then the classic approach. Second, according to the authors’ knowledge, currently there are no commercially available APFs, which allow to directly apply the optimization method in industrial applications. Practical implications – The presented results showed that the approach, which is the most popular in the industry, is far from being optimal from the cost perspective. As it has been shown in the investigated example, it might be possible to significantly reduce the total cost of APFs installed in the power system. Originality/value – The optimization method presented in the paper as well as all simulation results are the original authors work. It was shown that the existing harmonic compensation strategies can be significantly upgraded and the proposed optimization method may be a basis and a reference point for future commercial solutions.

Different Methods of Artificial Intelligence Used for Optimization the Turning Process

2015 ◽  
Vol 808 ◽  
pp. 60-65
Author(s):  
Nicolae Cofaru ◽  
Adrian Florea
Keyword(s):  
Random Variable ◽  
Cutting Parameters ◽  
Optimization Method ◽  
Optimization Techniques ◽  
Multi Objective Optimization ◽  
Software Application ◽  
Random Weights ◽  
The Cost ◽  
Optimal Cutting Parameters ◽  
Cost Components

In this paper, we realize a comparative study between some heuristics methods applied in turning operation in order to find optimal cutting parameters. We consider five different constraints aimed to achieve minimum total cost of machining. We have chosen the Simulated Annealing (SA) – a local search method, and Weighted-Sum Genetic Algorithm (WSGA) – a non-Pareto approach of a multi-objective optimization algorithm, based on a weighted aggregation of objectives. The aggregation may be with fixed weights or with random (variable) weights. The simulations showed that, even if it produces better results than the SA, WSGA with fixed weights, does not lead to optimum results, highlighting in this way that in the formula of the cost function, some cost components may be more important than others. In addition, we extend our previous work by integrating in the software application a new optimization method: WSGA with random weights. Also, we increase the application’s flexibility by reconfiguring the graphical user interface in order to allow tuning the optimization techniques parameters.

The cost-effectiveness of insulin analogs and regular insulin for diabetes control: a case study in Iran

2020 ◽  
Vol 33 (4/5) ◽  
pp. 323-331
Author(s):  
Mohsen pakdaman ◽  
Raheleh akbari ◽  
Hamid reza Dehghan ◽  
Asra Asgharzadeh ◽  
Mahdieh Namayandeh
Keyword(s):  
Cost Effectiveness ◽  
Cost Effective ◽  
Regular Insulin ◽  
Diabetes Control ◽  
Diabetic Patients ◽  
Insulin Analogs ◽  
Content Type ◽  
Patients With Diabetes ◽  
The Government ◽  
The Cost

PurposeFor years, traditional techniques have been used for diabetes treatment. There are two major types of insulin: insulin analogs and regular insulin. Insulin analogs are similar to regular insulin and lead to changes in pharmacokinetic and pharmacodynamic properties. The purpose of the present research was to determine the cost-effectiveness of insulin analogs versus regular insulin for diabetes control in Yazd Diabetes Center in 2017.Design/methodology/approachIn this descriptive–analytical research, the cost-effectiveness index was used to compare insulin analogs and regular insulin (pen/vial) for treatment of diabetes. Data were analyzed in the TreeAge Software and a decision tree was constructed. A 10% discount rate was used for ICER sensitivity analysis. Cost-effectiveness was examined from a provider's perspective.FindingsQALY was calculated to be 0.2 for diabetic patients using insulin analogs and 0.05 for those using regular insulin. The average cost was $3.228 for analog users and $1.826 for regular insulin users. An ICER of $0.093506/QALY was obtained. The present findings suggest that insulin analogs are more cost-effective than regular insulin.Originality/valueThis study was conducted using a cost-effectiveness analysis to evaluate insulin analogs versus regular insulin in controlling diabetes. The results of study are helpful to the government to allocate more resources to apply the cost-effective method of the treatment and to protect patients with diabetes from the high cost of treatment.

scholarly journals An Adaptive Optimization Method Based on Learning Rate Schedule for Neural Networks

2021 ◽  
Vol 11 (2) ◽  
pp. 850
Author(s):  
Dokkyun Yi ◽  
Sangmin Ji ◽  
Jieun Park
Keyword(s):  
Artificial Intelligence ◽  
Cost Function ◽  
Numerical Experiments ◽  
Global Minimum ◽  
Optimization Method ◽  
Learning Method ◽  
Adaptive Optimization ◽  
The Cost ◽  
Proof Of Convergence ◽  
Learning Data

Artificial intelligence (AI) is achieved by optimizing the cost function constructed from learning data. Changing the parameters in the cost function is an AI learning process (or AI learning for convenience). If AI learning is well performed, then the value of the cost function is the global minimum. In order to obtain the well-learned AI learning, the parameter should be no change in the value of the cost function at the global minimum. One useful optimization method is the momentum method; however, the momentum method has difficulty stopping the parameter when the value of the cost function satisfies the global minimum (non-stop problem). The proposed method is based on the momentum method. In order to solve the non-stop problem of the momentum method, we use the value of the cost function to our method. Therefore, as the learning method processes, the mechanism in our method reduces the amount of change in the parameter by the effect of the value of the cost function. We verified the method through proof of convergence and numerical experiments with existing methods to ensure that the learning works well.

Evaluating the cost and benefits of earthquake protection of buildings

2018 ◽  
Vol 11 (2) ◽  
pp. 263-278 ◽  
Author(s):  
Benedetto Manganelli ◽  
Marco Vona ◽  
Pierfrancesco De Paola
Keyword(s):  
Real Estate ◽  
Seismic Risk ◽  
Risk Mitigation ◽  
Tax Incentives ◽  
Seismic Retrofitting ◽  
Content Type ◽  
Seismic Risk Mitigation ◽  
The Cost ◽  
Earthquake Protection ◽  
Real Estate Assets

Purpose The purpose of this study is the evaluation of the cost and benefits of earthquake protection of buildings to verify whether the legislative push, through tax incentives, will produce results and lead to a redevelopment of private real estate assets. Design/methodology/approach Through contingent valuation, this research aims to measure the propensity of homeowners to invest in the seismic security of their properties. The sample of homeowners was selected in a southern Italy city, which was characterized by a medium-high seismic hazard. The willingness to pay, once made independent from the family income, was compared with the actual cost of a seismic retrofitting technique to assess its cost-effectiveness. Findings The analysis developed on an example case shows that the economic sustainability of the intervention is only verified when considering the current tax incentives for this type of intervention. Practical implications Choosing to introduce a system to compulsory insurance against seismic risk could certainly be a strong incentive for the implementation of retrofitting interventions on private real estate assets. In this direction, investigations like this can be fundamental to establish the fair risk premium. Originality/value The need for effective seismic risk mitigation policies is also based on the growing awareness of the, often fatal, effects of seismic events, emphasized by the recent medium and high intensity events that hit Italy. The issue of the security of residential buildings is therefore a very topical issue in view of their high seismic vulnerability and the vast number of buildings requiring major seismic retrofitting. Therefore, the propensity of owners to intervene in improving the seismic performance of their properties can be crucial in seismic risk mitigation.

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