Design for Reliability
Design for Reliability represents a proactive engineering philosophy that integrates reliability considerations into every phase of product development rather than attempting to test reliability into products after design completion. This approach recognizes that the majority of product reliability is determined during the design phase, when fundamental decisions about architecture, component selection, materials, and operating margins establish the inherent reliability capability of the product.
Effective design for reliability requires understanding the relationship between design decisions and failure mechanisms, applying appropriate analysis techniques to identify and mitigate potential reliability problems, and establishing design guidelines that encode reliability best practices. The methods and principles in this section help engineers make informed decisions that balance reliability against other design constraints such as cost, performance, size, and time to market.
Topics
Derating and Margin Design
Enhance reliability through conservative design practices. Coverage includes component derating guidelines, electrical stress derating, thermal derating factors, mechanical stress margins, voltage margin requirements, current limiting design, power dissipation management, frequency derating considerations, environmental derating, safety factor determination, industry-specific standards, military derating standards, commercial practices, and margin verification testing.
Redundancy and Fault Tolerance
Design systems that survive failures. Topics include redundancy architectures, active and standby redundancy, voting systems design, fault detection methods, fault isolation techniques, automatic reconfiguration, graceful degradation strategies, common cause failure analysis, diversity implementation, software redundancy methods, error correction codes, checkpoint and rollback, byzantine fault tolerance, and fail-safe design principles.
Reliability Prediction Methods
Estimate product reliability early in development using systematic prediction approaches. Coverage includes parts count prediction, parts stress analysis, MIL-HDBK-217 methodology, Telcordia SR-332, FIDES methodology, physics of failure models, similarity analysis techniques, field data correlation, uncertainty quantification, sensitivity analysis, worst-case analysis, thermal modeling integration, mechanical stress analysis, and software reliability prediction.
Robust Design Methods
Create designs insensitive to variation. Coverage encompasses Taguchi methods application, design of experiments, parameter optimization, tolerance design, signal-to-noise ratios, orthogonal array selection, interaction analysis, confirmation experiments, process capability studies, statistical tolerancing, worst-case analysis, Monte Carlo tolerance analysis, sensitivity analysis methods, and variation reduction techniques.
About This Category
Design for Reliability transforms reliability engineering from a quality assurance function into an integral part of the design process. Rather than discovering reliability problems through testing or field failures, design for reliability techniques help engineers anticipate and prevent problems before they occur. This proactive approach reduces development costs by avoiding expensive redesign cycles, shortens time to market by eliminating reliability-driven delays, and improves product quality by building reliability into the design from the start.
The principles of design for reliability apply across all electronics applications, from consumer products where reliability affects customer satisfaction and warranty costs to safety-critical systems where reliability directly impacts human safety. By mastering these techniques, engineers can consistently deliver products that meet reliability requirements while optimizing other design objectives.