Reliability and maintainability management-related tasks in the product life cycle

To obtain the desired level of reliability of a product/system in the field, a series of management tasks in regard to reliability and maintainability must be conducted throughout the system life cycle. The system life cycle may be divided into four phases, as shown in Fig. 5.1 [7].

System/product life cycle phases

Figure 5.1 System/product life cycle phases.

The reliability and maintainability management-related tasks involved in each of these four phases are as follows:

Concept and definition phase

In this phase, system-related requirements are established and the basic characteristics are defined. During this phase, various reliability- and maintainability-related management tasks are conducted. Some of them are as follows:

  • • Defining system safety requirements.
  • • Defining a failure.
  • • Defining the basic maintenance philosophy.
  • • Defining the system capability requirements, management controls, part control requirements, and terms used.
  • • Defining the system reliability and maintainability goals and quantitative terms.
  • • Defining methods to be used during the design and manufacturing phase.
  • • Defining system environmental factors during its life cycle.
  • • Defining hardware and software standard documents to be used for fulfilling reliability and maintainability requirements.
  • • Defining constraints proven to be harmful to reliability.
  • • Defining the management controls needed for documentation.

Acquisition phase

This phase is concerned with activities associated with system acquisition and installation as well as planning for eventual support of the system. In this phase, there are many reliability and maintainability management-associated tasks. Some of these tasks are as follows:

  • • Define all the system technical requirements, design and development methods to be employed, type of evaluation methods to be used for assessing the system, demonstration requirements, and documents required as part of the final system.
  • • Define the kind of reviews to be conducted.
  • • Define all the reliability and maintainability requirements that must be satisfied.
  • • Define the type of field studies, if any, to be performed.
  • • Define the meaning of a degradation or a failure.
  • • Define the kind of logistics support needed.
  • • Define the cost-related restraints and the life cycle cost information to be developed.
  • • Define the type of data to be supplied by the manufacturer to the customer.

Operation and maintenance phase

This phase is concerned with tasks related to the maintenance activity, management of the engineering, and the support of the system over its entire operational life. Some of the reliability- and maintainability-related management tasks involved during this phase are as follows:

  • • Providing adequate maintenance tools and test equipment.
  • • Establishing failure data banks.
  • • Providing adequate and appropriately trained manpower.
  • • Preparing maintenance-related documents.
  • • Managing and predicting spare parts.
  • • Reviewing the documentation with respect to any engineering change.
  • • Collecting, monitoring, and analyzing reliability and maintainability data.
  • • Developing engineering change proposals.

Disposal phase

This phase is concerned with tasks that are needed for removing the system and its nonessential supporting material. Two of the reliability and maintainability management-associated tasks involved in this phase are estimating the final system life cycle cost and the reliability and maintainability values. The resulting life cycle cost takes into consideration the disposal action income or cost.

The final reliability and maintainability values are computed for the buyer of the used system as well as for use in purchasing of similar systems.

Reliability management documents and tools

Reliability management makes use of a variety of documents and tools. Some examples of these documents are in-house reliability manual, documents explaining policy and procedures, instructions and plans, international standards and specifications, and reports and drawings [7]. Similarly, some of the tools used by reliability management are critical path method (CPM), value engineering, and configuration management.

Some of the above items are described below.

Reliability manual

This is the backbone of any reliability organization. Its existence is very important for any organization irrespective of its size. A typical reliability manual covers items such as follows:

  • • Organizational responsibilities and structure.
  • • Product design phase-related procedures with respect to reliability.
  • • Failure data collection and analysis procedures and methods to be followed.
  • • Relationship with customers and suppliers.
  • • Reliability test and demonstration procedures and approaches.
  • • Company-wide reliability policy.
  • • Effective reliability methods, models, and so on.

Value engineering

This is a systematic and creative technique used for accomplishing a required function at the minimum cost [8]. Historical records indicate that the application of this technique has returned between $15 and $30 for each dollar spent [9].

There are many areas in which value engineering is useful including the following:

  • • Generating new ideas to solve problems.
  • • Highlighting areas requiring attention and improvement.
  • • Servicing as a vehicle for dialogue.
  • • Increasing the value of goods and services.
  • • Prioritizing.
  • • Assigning dollars on high-value items.
  • • Determining and quantifying intangibles.

Additional information on value engineering is available in Ref. [10].

Configuration management

During the development of an engineering system, many changes may take place; these changes may be concerned with system performance, size, weight, and so on. In such situation, configuration management is considered a useful tool for assuring the customer and the manufacturer that the end system/product will fully satisfy the contract specification. Thus, configuration management may be defined as the management of technical requirements which defines the engineering system/product as well as changes thereto.

The history of configuration management goes back to 1962, when the U.S. Air Force released a document entitled 'Configuration Management During the Development and Acquisition Phases', AFSCM 375-1 [9]. Nowadays, configuration management is well known in the industrial sector, and its benefits include formal establishment of objectives, reduction in overall cost, elimination of redundant efforts, precisely identified final system/product, facilitation of accurate data retrieval, and effective channeling of resources.

Additional information on configuration management is available in Ref. [11].

Critical path method (CPM)

This method along with the program evaluation and review technique (PERT) is often used for planning and controlling projects. It was developed in 1956 by E.I. DuPont de Nemours and company for scheduling design- and construction-associated activities [12]. The following six general steps are associated with CPM:

  • Step I: Break down the project under consideration into individual tasks/jobs.
  • Step II: Arrange the tasks/jobs into a logical network.
  • Step III: Estimate the duration time of each task/job.
  • Step IV: Develop a schedule.
  • Step V: Highlight tasks/jobs that control the completion of the project.
  • Step VI: Redistribute resources and funds for improving the schedule.

There are many advantages of CPM. Some of these are: it identifies critical work activities for completing the project on time, determines project duration systematically, determines the need for labor and resources in advance, shows interrelationships in work flow, and improves communication and understanding.

Additional information on CPM is available in Ref. [13].

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