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ANSYS 2019 R3

What Is DFMEA?

Design failure mode and effect analysis (DFMEA) is a systematic group of activities used to recognize and evaluate potential systems, products or process failures. DFMEA identifies the effects and outcomes of these failures or actions. It eliminates or mitigates the failures and provides a written history of the work performed.

Failure mode and effective analysis (FMEA) is an important part of the design cycle, hence the creation of DFMEA.

With such a broad application, it sounds like DFMEA could be all things to all people. However, it is not the best analysis tool for every challenge. So, is it the best solution for you? Read on to find out.

The Industries Served by DFMEA

Many industries can benefit from DFMEA.

In essence, DFMEA determines what might go wrong, how bad the effect may be and how to prevent or mitigate it.

DFMEA helps engineers detect failures at the earliest possible moment so they can be corrected early, without significant cost. It is especially useful for disciplines in which risk reduction and failure prevention are crucial, including:

  • Manufacturing
  • Software
  • Business processes
  • Healthcare
  • Service industries
  • Regulated industries

The DFMEA Process

A DFMEA RPN distribution

DFMEA drills into failure from several angles to determine why the expected or intended function didn’t occur under the stated conditions. There are four areas of analysis:

  • Failure mode: the way in which a failure is observed
  • Failure effect: the immediate consequences of a failure on the operation, function or functionality
  • Failure cause: the underlying cause of the failure, or things which initiate processes which lead to failure (such as a defect in design, system, process, quality or part application)
  • Severity: the consequences of a failure mode, framed in the worst-case outcome, degree of injury, property damage or harm

The results are then taken to a more granular level with the calculation of a risk priority number (RPN) based on several variables:

  • Severity of the failure effect (SEV): a value applied on a scale of 1 (low) to 10 (high)
  • Frequency of failure occurrence (OCCUR): a value applied on a scale of 1 (infrequent) to 10 (frequent)
  • Detectability/preventability (DETEC): a value assigned on a scale of 1 (very detectable) to 10 (not detectable)

RPN is determined by multiplying SEV, OCCUR and DETEC. Therefore, the RPN can have a value anywhere from 1 (low risk) to 1,000 (high risk). Users are then able to define what is acceptable and unacceptable for the failure being analyzed.

Common DMFEA Mistakes

Avoid common mistakes in the DFMEA process

Like any process, DFMEA is subject to some degree of user error.

Some obvious lapses include never referencing or updating DMFEA documentation or applying the analysis inconsistently.

Procedurally, there are a number of missteps that can also occur:

  • Misunderstanding the DFMEA scope and objective
  • Skipping the process of design control
  • Skipping failure mode, cause and effect separation
  • Ranking criteria too closely
  • Identifying only problems — not solutions
  • Having no control plan in place when a solution exists

Some of these mistakes may be the result of users trying to save time during the long DFMEA process. With ANSYS Sherlock automated design analysis software, users can economize DFMEA testing time without compromising quality or outcomes.

ANSYS Sherlock and DFMEA

Sherlock is an automated design analysis software that introduces insight and prediction into product development at a much earlier stage than other methodologies. As an alternative to physical testing, Sherlock models the design and uses it to provide dependable analysis.

Sherlock prepopulates a DFMEA spreadsheet using imported netlists.

DFMEA with Sherlock helps:

  • Automate many time-consuming processes
  • Comply with AIAG, SAE J1739 and ISO S26262 standards
  • Prepopulate the analysis spreadsheet using reference designators, component technology and failure mode information from standard design files (e.g., bill of materials and netlists)

Sherlock automates and simplifies DFMEA, increasing the value of this important analysis process across all industries and disciplines in which it is used.

To learn more, read about Sherlock’s capabilities. Or register for the webinar: Introduction to Reliability Physics Analysis.

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