Design Verification and Validation

1. Design Verification and Validation Multidisciplinary Capstone Design Spring 2010 Jay R. Goldberg, PhD, PE

2. 1-10-100 Rule

3. Verification and Validation Design output = Design input Validation: Did we make the right product? (Does the product meet customer needs?) Verification: Did we make the product right? (Do our processes ensure that the product will do what it is design to do?)

4. Verification and Validation • Required by ISO 9000 family of standards, regulatory agencies • Ethical obligation to customer to ensure that product works and is safe to use • Good engineering/design practice • Reduces liability

5. Testing Analytical modeling Bench Testing Package Testing Field Testing Product Introduction Shelf-life Studies

6. Testing (Medical Devices) Biocompatibility Tests Bench Tests Animal Studies Human Clinical Studies Product Introduction Package Tests Shelf-life Studies

7. Bench Testing • Test per industry standards (if available) • Use/simulate production processes to produce test units • same tooling, assembly methods, processes, sterilization, etc. • Simulate use/function of product in laboratory • Simulate service environment (environmental testing) • mechanical and electrical loading • lubrication, wear conditions • fluid composition, concentration, Tº, pH • magnetic fields, other energy sources • flow rates

8. Bench Testing • Test for minimum number of cycles or hours until failure, or for expected service life • Monitor performance characteristics during testing • flow rates • wear debris • voltage output, leakage current • mechanical deformation, change in material properties

9. Bench Testing • Inspect device for signs of degradation, changes with continued use • out of calibration, decreased sensitivity/accuracy • wear, corrosion, oxidation • product failure (no longer functions) • loss of physical properties (strength, flexibility) • discoloration • obstruction, kinking • fracture

10. Field Testing • Analytical models are not definitive, must test actual product • Should be tested in environment where it will be used • Testing helps identify needed design changes • Conduct prior to market release to prevent defective or inadequate designs (those that do not meet customer needs) from entering market • Software – Beta test sites • Consumer products – limited market release • Medical products – human clinical study

11. Benefits of Field Testing • R&D: helps identify where improvements are needed • Marketing/Sales: provides data to help sell product, compete in market • Regulatory: provides data to obtain necessary approvals to market product

12. Automobile Suspension Testing Bench testing Field testing

13. Electronic Devices • Variety of required tests for US & EU • Leakage current • Electromagnetic Compatibility (EMI, immunity)

14. Consumer Products

15. Consumer Products

16. Fatigue Testing

17. Usability Studies Customer Service Contact Center Website testing

18. Medical Devices • Loading • magnitude • frequency • number of cycles • range of motion • Environment • temperature • chemical composition • proteins • pH • [Cl-]

19. Software Validation • ISO/IEC 12207 Software Life Cycle Processes • IEEE/IEC 1012aStandard for Software Verification and Validation

20. Biocompatibility Tests • Need to ensure that materials • remain stable • do not significantly degrade • do not harm body (not toxic, etc.) • are not adversely affected by processes (sterilization, lubricants, mold releases, cleaning agents, etc.)

21. Animal Studies • Requirements: • appropriate animal model • written protocol • approval of animal use committee • Test for safety and efficacy • monitor performance of device • perform histological evaluation • inspect for damage to tissues, organs, structures

22. Human Clinical Studies • Rationale: • Cannot exactly duplicate physiological environment in lab • Animal models not identical to human model • Need to conduct human clinical study to accurately evaluate performance of device in humans, verify claims • Will often encounter new problems in clinical study that were not observed in animal study or bench testing.

23. Package Testing • Distribution simulation • conduct on final product • simulate environmental variables • temperature • humidity • pressure • simulate distribution history • manual handling test • stacking test • vehicle vibration test

24. Package Testing

25. Package Testing • Inspect all packaging for signs of damage • migration of components in package, resulting in damage to components, product, or package • Conduct tests on sterile packaging materials • burst test, leak test • Evaluate device • inspect for damage to packaging and product • perform functional tests on product

26. Shelf-Life Testing • Determine how long product can sit on shelf with no significant changes in physical properties or performance • product • sterile packaging • Testing allows determination of shelf-life of product

27. Shelf-Life Testing • Real time shelf life studies • conduct distribution simulation • simulate storage environment • evaluate product and packaging for changes in properties and function over time • Accelerated aging studies • higher temperature, reduced time • must be correlated with real-time study

28. Shelf Life Study - Example MW Molecular Weight vs. Time Shelf life Desired Minimum Minimum acceptable Time

29. Shipping Shipping Shipping Storage in Warehouse Summary of Packaging/Shelf-Life Testing Packaging Sterilization Aging Storage in Customer Warehouse Use of Product

30. Summary of Testing • Subject product to all potential performance affecting variables. • sterilization • distribution simulation • aging • If product is functional with no significant changes in physical properties, can assume will perform acceptably when package is opened and product used