Design for Reliability

Design for Reliability

In order to be profitable, an organization’s products must be reliable, and reliable products require a formal reliability process. Three important statements summarize the best practice reliability philosophy of successful companies:

  • Reliability must be designed into products and processes using the best available science-based methods.
  • Knowing how to calculate reliability is important, but knowing how to achieve reliability is equally, if not more, important.
  • Reliability practices must begin early in the design process and must be well integrated into the overall product development cycle.

Understanding when, what and where to use the wide variety of reliability engineering tools available will help to achieve the reliability mission of an organization. And this is becoming more and more important with the increasing complexity of systems as well as the complexity of the methods available for determining their reliability. System interactions, interfaces, complex usage and stress profiles need to be addressed and accounted for. With such increasing complexity in all aspects of product development, it becomes a necessity to have a well-defined process for incorporating reliability activities into the design cycle. Without such a process, trying to implement all of the different reliability activities involved in product development can become a chaotic situation, where different reliability tools are deployed too late, randomly, or not at all, resulting in the waste of time and resources as well as the occurrence of problems in the field.

Design for Reliability is a structured methodology that ensures to design reliability into operation. It is an emerging discipline that refers to the process of designing reliability into products as opposed to the Test-Analyze-and-Fix philosophy (Weibull Analysis or Life Data Analysis) which are based on part-count failure rate taken from historical data and are used to predict product reliability.

The reality is that performing life data analysis is not enough to achieve reliable products. Rather, there are a variety of activities involved in an effective reliability program and in arriving at reliable products. Achieving the organization’s reliability goals requires strategic vision, proper planning, sufficient organizational resource allocation and the integration and institutionalization of reliability practices into development projects.

The use of design-for-reliability techniques can help to identify the components that need modification early in the design stage when it is much more cost-effective to institute such changes.

DFR is actually a process that describes the entire set of tools which support product and process design (typically from early in the concept stage all the way through to product obsolescence) to ensure that customer expectations for reliability are fully met throughout the life of the product with low overall life-cycle costs. In other words, the process of designing for reliability involves looking at the application's expected usage pattern, specifying the required reliability profile, and engineering the software architecture with the intention of meeting the profile. It is a systematic, streamlined, concurrent engineering program in which reliability engineering is weaved into the total development cycle.

Understanding the reliability problems and solutions for a system you have not built yet is not easy, but a good place to start is with analysis of your currently running applications. Such analysis should reveal the failure frequency and distribution, root causes, and possible improvements for existing systems. Armed with current operational data, you can leverage the current reliability knowledge into a better design for the new system.

As a design concept, reliability is about an operations ability to operate failure free. This includes ensuring accurate data input and data transformations, error-free state management, and non-corrupting recovery from detected failure conditions.

Objectives of Design for Reliability - DFR:

  • Develop mathematical models for predicting, analyzing and improving product reliability,
  • Ensure that product failure modes are detected and occur beyond the specified lifetime period,
  • Sustain product function robustness over specified lifetime under real-world usage conditions.

Arrelic Expertise in DFR

The reliability experts of Arrelic have developed a Design for Reliability (DFR) model that integrates well in your product development process and ensures successful operations. It includes the following reliability analysis techniques:

  • Lifetime Data Analysis (MTTF, MTBF,MTTR, etc.),
  • Lifetime Model Selection & Fitting,
  • Reliability Target Setting & Allocation,
  • Reliability Block Diagram Analysis,
  • Fault Tree Analysis (FTA),
  • Failure Mode & Effects Analysis (FMEA),
  • Reliability Improvement Plan,
  • System Reliability Modeling and Prediction,
  • Highly Accelerated Life Testing (HALT),
  • Highly Accelerated Stress Testing (HAST),
  • Highly Accelerated Stress Screening (HASS),
  • Reliability Growth Analysis,
  • Reliability Demonstration.

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