A time-varying reliability-based robust design method considering overall efficiency of axial piston pump

2021 ◽  
pp. 1748006X2110661
Author(s):  
Zunling Du ◽  
Yimin Zhang
Keyword(s):  
Energy Conversion ◽  
Robust Design ◽  
Design Method ◽  
Design Stage ◽  
Structure Parameters ◽  
Time Varying ◽  
Design Variables ◽  
Reliability Method ◽  
Overall Efficiency ◽  
Axial Piston

Axial piston pumps (APPs) are the core energy conversion components in a hydraulic transmission system. Energy conversion efficiency is critically important for the performance and energy-saving of the pumps. In this paper, a time-varying reliability design method for the overall efficiency of APPs was established. The theoretical and practical instantaneous torque and flow rate of the whole APP were derived through comprehensive analysis of a single piston-slipper group. Moreover, as a case study, the developed model for the instantaneous overall efficiency was verified with a PPV103-10 pump from HYDAC. The time-variation of reliability for the pump was revealed by a fourth-order moment technique considering the randomness of working conditions and structure parameters, and the proposed reliability method was validated by Monte Carlo simulation. The effects of the mean values and variance sensitivity of random variables on the overall efficiency reliability were analyzed. Furthermore, the optimized time point and design variables were selected. The optimal structure parameters were obtained to meet the reliability requirement and the sensitivity of design variables was significantly reduced through the reliability-based robust design. The proposed method provides a theoretical basis for designers to improve the overall efficiency of APPs in the design stage.

Exploring the Design Space Using a Surrogate Model Approach With Digital Human Modeling Simulations

2018 ◽  
Author(s):  
Salman Ahmed ◽  
Mihir Sunil Gawand ◽  
Lukman Irshad ◽  
H. Onan Demirel
Keyword(s):  
Human Factors ◽  
Surrogate Model ◽  
Human Performance ◽  
Design Method ◽  
Human Subjects ◽  
Design Stage ◽  
Digital Human Modeling ◽  
Design Variables ◽  
Human Modeling ◽  
Digital Human

Computational human factors tools are often not fully-integrated during the early phases of product design. Often, conventional ergonomic practices require physical prototypes and human subjects which are costly in terms of finances and time. Ergonomics evaluations executed on physical prototypes has the limitations of increasing the overall rework as more iterations are required to incorporate design changes related to human factors that are found later in the design stage, which affects the overall cost of product development. This paper proposes a design methodology based on Digital Human Modeling (DHM) approach to inform designers about the ergonomics adequacies of products during early stages of design process. This proactive ergonomics approach has the potential to allow designers to identify significant design variables that affect the human performance before full-scale prototypes are built. The design method utilizes a surrogate model that represents human product interaction. Optimizing the surrogate model provides design concepts to optimize human performance. The efficacy of the proposed design method is demonstrated by a cockpit design study.

Robust Design of Structures with Uncertain Parameters and Frequency Constraints Using Non-Probabilistic Methods

2014 ◽  
Vol 936 ◽  
pp. 1479-1484
Author(s):  
Ji Yun Chen ◽  
Yan Luo ◽  
Dong Huan Liu
Keyword(s):  
Robust Design ◽  
Measurement Errors ◽  
Design Method ◽  
Probabilistic Methods ◽  
Structural Performance ◽  
Stochastic Methods ◽  
Uncertain Parameters ◽  
Vibration Frequencies ◽  
Design Variables ◽  
Robust Design Method

The structural physical properties are often uncertain due to manufacture errors, measurement errors and other factors. Consequently, the vibration frequencies and corresponding eigenvectors are also uncertain. Robust design selects suitable design variables so that structural performance is insensitive to the various causes of variation without eliminating possible variations of variables. In practice robust design methods can be classified into probabilistic methods and non-probabilistic methods respectively. A new non-probabilistic robust design method based on the set theoretical convex method is presented in the present paper. The method not only inherits the advantages of existing non-stochastic methods, but also conquers the disadvantages of these methods.

Robust Design for Dynamic System Under Model Uncertainty

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
XinJiang Lu ◽  
Han-Xiong Li
Keyword(s):  
Robust Design ◽  
Model Uncertainty ◽  
Design Space ◽  
Design Method ◽  
Performance Constraints ◽  
Nominal Model ◽  
Traditional Design ◽  
Design Variables ◽  
Real World Applications ◽  
Robust Design Method

In real-world applications, a nominal model is often used to approximate the design of an industrial system. This approximation could make the traditional design method less effective due to the existence of model uncertainty. In this paper, a novel stability-based approach is proposed to design the system ensuring robust stability under model uncertainty. First, the design variables and their variation bounds are configured to make the system stable. Then, a robust design is developed to incorporate system eigenvalues that are less sensitive to model uncertainty. Finally, the tolerance of the design space will be maximized under given performance constraints. A simulation example is conducted to demonstrate the effectiveness of the proposed robust design method.

A Safety Factor Method for Reliability-Based Component Design

2021 ◽  
pp. 1-34
Author(s):  
Jianhua Yin ◽  
Xiaoping Du
Keyword(s):  
Safety Factor ◽  
Design Method ◽  
Deterministic Component ◽  
Reliability Based Design ◽  
Component Design ◽  
Design Variables ◽  
Wide Range ◽  
Reliability Method ◽  
Reliability Methods ◽  
Input Variables

Abstract Reliability-based design (RBD) identifies design variables that maintain reliability at a required level. For many routine component design jobs, RBD may not be practical as it requires nonlinear optimization and specific reliability methods, especially for those design jobs which are performed manually or with a spreadsheet. This work develops a practical approach to reliability-based component design so that the reliability target can be achieved by conducting traditional component design repeatedly using a deterministic safety factor. The new component design is based on the First Order Reliability Method, which iteratively assigns the safety factor during the design process until the reliability requirement is satisfied. In addition to several iterations of deterministic component design, the other additional work is the calculation of the derivatives of the design margin with respect to the random input variables. The proposed method can be used for a wide range of component design applications. For example, if a deterministic component design is performed manually or with a spreadsheet, so is the reliability-based component design. Three examples are used to demonstrate the practicality of the new design method.

RESEARCH ON THE FREQUENCY RELIABILITY SENSITIVITY AND RELIABILITY-BASED ROBUST DESIGN OF THE RANDOM VIBRATION SYSTEM OF CONTINUOUS ROD

2016 ◽  
Vol 40 (4) ◽  
pp. 469-479
Author(s):  
Chunmei Lü ◽  
Yimin Zhang ◽  
He Li ◽  
Na Zhou
Keyword(s):  
Robust Design ◽  
Random Vibration ◽  
Design Method ◽  
Random Parameter ◽  
Dynamic Structure ◽  
Stochastic Dynamic ◽  
Vibration System ◽  
Reliability Sensitivity ◽  
Reliability Method ◽  
Continuous Rod

The frequency reliability sensitivity in the stochastic dynamic structure system and reliability-based robust design were studied deeply in this paper. With the criterion that the absolute value of the difference between natural frequency and forcing frequency, the frequency reliability method of avoiding resonance was proposed. Then frequency reliability sensitivity theory was presented, which provided a preliminary efficient way to analyze how each random parameter contributed to the system reliability. Moreover, the frequency reliability-based robust design method was obtained by robust and optimization technology on the basis of the frequency reliability and sensitivity research in the paper, which helped designers to establish acceptable parameter values and to determine the fluctuations of the parameters for the safe operations. Meanwhile, a numerical example of the random vibration system of continuous rod was provided and studied. The effectiveness and accuracy of the proposed methods were well demonstrated.

scholarly journals Axiomatic Design Approach for Nonlinear Multiple Objective Optimizaton Problem and Robustness in Spring Design

2017 ◽  
Vol 17 (1) ◽  
pp. 63-71
Author(s):  
Ahmet Feyzioglu ◽  
A. Kerim Kar
Keyword(s):  
Robust Design ◽  
Design Method ◽  
Minimum Cost ◽  
Axiomatic Design ◽  
General Information ◽  
Design Approach ◽  
Design Stage ◽  
Independence Axiom ◽  
Multi Objective ◽  
Parameter Values

Abstract This paper gives general information about multi-objective, axiomatic and robust design approaches and considersasolution model of nonlinear multi-objective optimization problem based on applyinganew robust design approach. Both axiomatic and robust design approaches were used complementarily inacase study with distinct multi-objectives. In this case study, the main target was achieving each objective optimum to minimize the mass and the shear stress ofaspring by integrating robustness and durability at the design stage due to trade off between objectives. This spring problem was examined using the independence axiom of the axiomatic design methodology. Also, semangularity and reangularity concepts were used and design matrices were formed to find coupled and decoupled solutions. It was observed that there were some acceptable design parameter values for which the design became decoupled. Graphical and numerical results were checked to see if they were compatible with each other. Finally, this decoupled design was given appropriate tolerances by using robust design method. This way,arobust and durable spring was designed which would satisfy the given specifications with minimum cost in the existing literature from the view point of axiomatic design approach.

Perturbation Theory Based Robust Design Under Model Uncertainty

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
XinJiang Lu ◽  
Han-Xiong Li
Keyword(s):  
Perturbation Theory ◽  
Robust Design ◽  
Model Uncertainty ◽  
Design Method ◽  
Matrix Perturbation ◽  
Nominal Model ◽  
Design Variables ◽  
The Matrix ◽  
System Robustness ◽  
And Control

In real-world applications, a nominal model is usually used to approximate the practical system for design and control. This approximation may make the traditional robust design less effective because the model uncertainty still affects the system performance. In this paper, a novel robust design approach is proposed to improve the system robustness to the variations in design variables as well as the model uncertainty. The proposed robust design consists of two separate optimizations. One is to minimize the variation effects of the design variables to the performance based on the nominal model just as what the traditional deterministic robust design methods do. The other is to minimize the effect of the model uncertainty using the matrix perturbation theory. Through solving a multi-objective optimization problem, the proposed design can improve the system robustness to the uncertainty. Simulation examples have demonstrated the effectiveness of the proposed design method.

A Practical Safety Factor Method for Reliability-Based Component Design

2020 ◽  
Author(s):  
Jianhua Yin ◽  
Xiaoping Du
Keyword(s):  
Safety Factor ◽  
Design Method ◽  
Deterministic Component ◽  
Reliability Based Design ◽  
Component Design ◽  
Design Variables ◽  
Wide Range ◽  
Reliability Method ◽  
Reliability Methods ◽  
Input Variables

Abstract Reliability-based design (RBD) identifies design variables that maintain reliability at a required level. For many routine component design jobs, RBD may not be practical as it requires nonlinear optimization and specific reliability methods, especially for those design jobs which are performed manually or with a spreadsheet. This work develops a practical approach to reliability-based component design so that the reliability target can be achieved by conducting traditional component design repeatedly using a deterministic safety factor. The new component design is based on the First Order Reliability Method, which iteratively assigns the safety factor during the design process until the reliability requirement is satisfied. In addition to a number of iterations of deterministic component design, the other additional work is the calculation of the derivatives of the design margin with respect to the random input variables. The proposed method can be used for a wide range of component design applications. For example, if a deterministic component design is performed manually or with a spreadsheet, so it the reliability-based component design. Three examples are used to demonstrate the practicality of the new design method.

Multi-Objective Design Problem of Tire Wear and Visualization of Its Pareto Solutions2

2006 ◽  
Vol 34 (3) ◽  
pp. 170-194 ◽  
Author(s):  
M. Koishi ◽  
Z. Shida
Keyword(s):  
Inverse Problems ◽  
Conceptual Design ◽  
Dimensional Space ◽  
Design Stage ◽  
Objective Functions ◽  
Pareto Solutions ◽  
Design Problems ◽  
Multi Objective ◽  
Design Engineers ◽  
Design Variables

Abstract Since tires carry out many functions and many of them have tradeoffs, it is important to find the combination of design variables that satisfy well-balanced performance in conceptual design stage. To find a good design of tires is to solve the multi-objective design problems, i.e., inverse problems. However, due to the lack of suitable solution techniques, such problems are converted into a single-objective optimization problem before being solved. Therefore, it is difficult to find the Pareto solutions of multi-objective design problems of tires. Recently, multi-objective evolutionary algorithms have become popular in many fields to find the Pareto solutions. In this paper, we propose a design procedure to solve multi-objective design problems as the comprehensive solver of inverse problems. At first, a multi-objective genetic algorithm (MOGA) is employed to find the Pareto solutions of tire performance, which are in multi-dimensional space of objective functions. Response surface method is also used to evaluate objective functions in the optimization process and can reduce CPU time dramatically. In addition, a self-organizing map (SOM) proposed by Kohonen is used to map Pareto solutions from high-dimensional objective space onto two-dimensional space. Using SOM, design engineers see easily the Pareto solutions of tire performance and can find suitable design plans. The SOM can be considered as an inverse function that defines the relation between Pareto solutions and design variables. To demonstrate the procedure, tire tread design is conducted. The objective of design is to improve uneven wear and wear life for both the front tire and the rear tire of a passenger car. Wear performance is evaluated by finite element analysis (FEA). Response surface is obtained by the design of experiments and FEA. Using both MOGA and SOM, we obtain a map of Pareto solutions. We can find suitable design plans that satisfy well-balanced performance on the map called “multi-performance map.” It helps tire design engineers to make their decision in conceptual design stage.

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