Some Stochastic Mechanical Design Applications

1992 ◽  
Vol 114 (1) ◽  
pp. 42-47 ◽  
Author(s):  
C. R. Mischke
Keyword(s):  
Mechanical Design ◽  
Stochastic Methods ◽  
Strength Data ◽  
Weibull Parameters ◽  
The Third ◽  
Active Constraints ◽  
Stochastic Problems ◽  
Property Data ◽  
Machine Elements ◽  
Machinery Design

This is the third paper in a series relating to stochastic methods in mechanical design. The two previous ones were entitled, “Some Property Data and Corresponding Weibull Parameters for Stochastic Mechanical Design,” and “Fitting Weibull Strength Data and Applying it to Stochastic Mechanical Design.” They presented the groundwork for addressing stochastic problems in machinery design to a reliability goal when strength data are sparse. The purpose of this paper is to utilize procedures for estimating reliability of machine elements when yielding, fracture, or distortion are the limiting or active constraints.

Fitting Weibull Strength Data and Applying It to Stochastic Mechanical Design

1992 ◽  
Vol 114 (1) ◽  
pp. 35-41 ◽  
Author(s):  
C. R. Mischke
Keyword(s):  
Mechanical Design ◽  
Least Square ◽  
Stochastic Methods ◽  
Coordinate Transformations ◽  
Strength Data ◽  
The Third ◽  
Tension Tests ◽  
Property Data ◽  
Simple Tension ◽  
Best Fit

This is the second paper in a series relating to stochastic methods in mechanical design. The first is entitled, “Some Property Data and Corresponding Weibull Parameters for Stochastic Mechanical Design,” and the third, “Some Stochastic Mechanical Design Applications.” When data are sparse, many investigators prefer employing coordinate transformations to rectify the data string, and a least-square regression to seek the best fit. Such an approach introduces some bias, which the method presented here is intended to reduce. With mass-produced products, extensive testing can be carried out and prototypes built and evaluated. When production is small, material testing may be limited to simple tension tests or perhaps none at all. How should a designer proceed in order to achieve a reliability goal or to assess a design to see if the goal has been realized? The purpose of this paper is to show how sparse strength data can be reduced to distributional parameters with less bias and how such information can be used when designing to a reliability goal.

Some Property Data and Corresponding Weibull Parameters for Stochastic Mechanical Design

1992 ◽  
Vol 114 (1) ◽  
pp. 29-34 ◽  
Author(s):  
C. R. Mischke
Keyword(s):  
Goodness Of Fit ◽  
Mechanical Design ◽  
Stochastic Methods ◽  
Published Data ◽  
Short Supply ◽  
Strength Data ◽  
Weibull Parameters ◽  
Property Data ◽  
Strength Distributions

This is the first paper in a series of three relating to stochastic methods in mechanical design. The others are entitled, “Fitting Weibull Strength Data and Applying it to Stochastic Mechanical Design,” and “Some Stochastic Mechanical Design Applications.” The purpose of this paper is to present some Weibull parameters of strength distributions that were deduced from published histographic data. Stochastic materials data are in short supply; yet a closer look shows a surprising amount available. However, the published data may need to be interpreted and personal tests reduced. This paper shows histographic data that was converted to three-parameter Weibull distributional fits with relevant goodness-of-fit information displayed.

Nappes d'huile: prediction de leurs deplacements comme agent efficace d'un plan de mesure d'urgence

1979 ◽  
Vol 14 (1) ◽  
pp. 89-109
Author(s):  
B. Coupal ◽  
M. de Broissia
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Finite Elements ◽  
Mass Balance ◽  
Stochastic Method ◽  
Stochastic Methods ◽  
Deterministic Approach ◽  
First Order ◽  
The Third ◽  
Comme Agent

Abstract The movement of oil slicks on open waters has been predicted, using both deterministic and stochastic methods. The first method, named slick rose, consists in locating an area specifying the position of the slick during the first hours after the spill. The second method combines a deterministic approach for the simulation of current parameters to a stochastic method simulating the wind parameters. A Markov chain of the first order followed by a Monte Carlo approach enables the simulation of both phenomena. The third method presented in this paper describes a mass balance on the spilt oil, solved by the method of finite elements. The three methods are complementary to each other and constitute an important point for a contingency plan.

Analysis of Flexure Strength Data of Ceramics

1983 ◽  
Vol 105 (3) ◽  
pp. 219-223 ◽  
Author(s):  
S. G. Seshadri ◽  
M. Srinivasan
Keyword(s):  
Strength Distribution ◽  
Service Performance ◽  
Parameter Estimates ◽  
Reliability Data ◽  
Flexure Strength ◽  
Statistical Strength ◽  
Strength Data ◽  
Weibull Parameters ◽  
Surface Flaws ◽  
Test Population

A method to obtain the two and three Weibull parameters from the statistical strength distribution of ceramics, when either surface flaws or volumetric flaws govern fracture, is outlined. The advantages of obtaining confidence in the parameter estimates are given realizing the flaw severity variations within a test population. The inadequacy of testing a very limited number of specimens to gather reliability data to assess service performance is discussed.

System Optimization on Course Group of Modern Machinery Design Method

2012 ◽  
Vol 201-202 ◽  
pp. 812-815
Author(s):  
Ping Yuan Xi ◽  
Bing Wang
Keyword(s):  
Mechanical Design ◽  
Design Method ◽  
Effective Means ◽  
Technical Problem ◽  
System Optimization ◽  
Teaching Situation ◽  
Teaching Content ◽  
Practical Engineering ◽  
Rational Plan ◽  
Machinery Design

Modern machinery design method is the effective means to solve practical engineering technical problem, so it is very necessary to develop modern mechanical design thought and grasp modern mechanical design method. Through the teaching of the modern mechanical design method the students could grasp this method and the basic design means, and has certain solving ability to practical mechanical engineering problems in this method. In this paper we would thoroughly analyze the teaching situation of course group of "modern machinery design method"; and rational plan teaching content of course group, and according to the achievements in scientific research of teachers, develop appropriate teaching courseware and teaching software in teaching.

Functional Analysis Diagrams With the Representation of Movement Transitions

2013 ◽  
Author(s):  
Szu-Hung Lee ◽  
Pingfei Jiang ◽  
Peter R. N. Childs ◽  
Keith Gilroy
Keyword(s):  
Functional Analysis ◽  
Conceptual Design ◽  
Design Process ◽  
Mechanical Design ◽  
Functional Requirements ◽  
Design Structure ◽  
Machine Elements ◽  
Physical Elements ◽  
Types Of Information

A study on utilising a graphical interface to represent movement transmission within products has been conducted to support a creative conceptual design process that separates the consideration of functional requirements and motion requirements. In engineering design, many representations of product structure have been proposed to assist in understanding how a design is constituted. However, most of these representations demonstrate only functions and are not able to demonstrate design structure. Functional Analysis Diagrams (FAD) provides a solution for this. An FAD shows not only functions but also physical elements by the network of blocks and arrows and thus it is capable of demonstrating various types of information and the design scheme. This characteristic gives FADs an advantage for designers to combine different types of information including useful and harmful interactions to gain an overview of the design task. This study focuses on using circles instead of arrows to represent movement attributes of mechanisms and machine elements in a Kinematic Functional Analysis Diagram (KFAD) and explores methods of utilising it in mechanical design. A commercial case study of medical equipment design conducted with the assistance of KFADs and a component database, mechanism and machine elements taxonomy (MMET), is described to illustrate the process. The design outcome shows that it is feasible to follow the proposed conceptual design process. With the help of KFADs and the machine elements taxonomy to enable consideration of movements, diverse considerations and design solutions are possible.

scholarly journals A New Concept of the Mechanism of Variation of Tribological Properties of the Machine Elements Interacting Surfaces

2020 ◽  
Author(s):  
George Tumanishvili ◽  
Tengiz Nadiradze ◽  
Giorgi Tumanishvili
Keyword(s):  
Contact Zone ◽  
Tribological Properties ◽  
High Speed ◽  
Third Body ◽  
The Third ◽  
The Coefficient Of Friction ◽  
Speed Up ◽  
Machine Elements ◽  
Interacting Surfaces ◽  
Experimental Researches

The methods of estimation and prediction of tribological properties of the contact zone of interacting elements of machines are characterized by the low informativeness and accuracy that complicates provision of the proper tribological properties and hinders reliable and effective operation of machines. For obtaining more wide information about factors influencing tribological properties of the interacting surfaces, the experimental researches on the high speed (up to 70-m/s) and serial twin-disk machines were carried out. Our researches have shown that with different properties and degrees of destruction of the third body, the coefficient of friction can change up to 10 times or more, the wear rate up to 102-104 times, etc. This was the basis for a new concept of the mechanism of variation of tribological properties of interacting surfaces. The researches have shown a dependence of tribological properties of the contact zone on the properties and destruction degree of the third body that was assumed as a basis of new concept of the mechanism of variation of tribological properties of these surfaces. The monitoring of the third body destruction onset and development was carried out in the laboratory conditions and a criterion of the third body destruction was developed. The reasons of the negative, neutral and positive friction and mild, severe and catastrophic wear are shown.

Tensile Testing for Design

2004 ◽  
pp. 91-100
Keyword(s):  
Mechanical Testing ◽  
Tensile Testing ◽  
Mechanical Design ◽  
Material Selection ◽  
Mechanical Test ◽  
General Relation ◽  
Test Methods ◽  
Design Criterion ◽  
Property Data ◽  
Basic Objective

Abstract This chapter introduces the basic concepts of mechanical design and its general relation with the properties derived from tensile testing. It begins with a description of the basic objective of product design. Next, a simple tie bar is used to illustrate the application of mechanical property data to material selection and design and to highlight the general implications for mechanical testing. Material subjected to the basic stress conditions is considered in order to establish design approaches and mechanical test methods, first in static loading and then in dynamic loading and aggressive environments. The chapter then briefly describes design criteria for some basic property combinations such as strength, weight, and costs as well as another important design criterion, that is stiffness in tension. Additionally, it describes the processes involved in mechanical testing for stress at failure and elastic modulus. Finally, the chapter examines the correlation between hardness and strength.

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