Integrated customer-oriented reliability and robust design for reliable products

مقدم أطروحة جامعية

Salim, Kazim Abd Ahmad

مشرف أطروحة جامعية

al-Zubaydi, Sawsan Subayh
Qassam, Ala al-Din Hasan

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم هندسة الإنتاج و المعادن

دولة الجامعة

العراق

الدرجة العلمية

دكتوراه

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

-The accuracy of reliability estimation depends on the models that relate the degradation data under severe conditions, or high stress, to that at normal operating conditions, or design stress.

Hence a customer -oriented reliability strategy for better utilization of the information from actual use would play an important role in achieving high reliability.

Reliability is considered the performance of a product over time and it is the probability that a product will operate adequately for a given period in its intended application.

The random variables of interest are numbers of defects and degree of conformance.

As complexity grows, reliability is threatened.

The present research is concentrated on constructing and developing mathematical model based on accelerated degradation tests called nonparametric proportional odds-based Accelerated Degradation Tests (ADT) model which consists of two parts multi time regression and covariate function.

Then developing nonparametric proportional odds model under single, multiple and time dependent covariate.

Also developing the parameters estimation procedures by approximating the general baseline odds function with a polynomial function.

The main importance of the mathematical nonparametric proportional odds model is to decrease the total degradation test time.

The confidence intervals of the unknown parameters and the predicted reliability at the design stress level are obtained parametric and nonparametric.

Also predict the interval of reliability at different customer use which represents the variance of customer environment covariates as time independent covariate and then covariate expression to time dependent covariate is developed so as to get reliability changes.

The experimental testing was conducted using LED and DC motors.

The test units are subjected to different stress types and one time dependent stress type.

The LED tests were done continuously for 250 hours for each test and 96 hours for DC motor.

The results validate the applicability of the proportional odds based accelerated degradation test models and are compared with parametric model for reliability interval.

The proportional model in this dissertation only considers time-constant coefficients and time dependent for one stress type only.

It should be extended to incorporate time-varying coefficients for both baseline odds function and stress effects.

This will accommodate situations where the applied stress is time-dependent for two types of stress.

In the dissertation, it is assumed that the effects of different stress types are not correlated.

The correlations of different stress types should be considered in future research for more practical cases.

التخصصات الرئيسية

الهندسة المدنية

الموضوعات

• المواصفات القياسية
• ضمان الجودة

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-304937