Durability assessment

Accelerated tests are often performed to shorten the time needed for durability tests. Accelerated tests are carried out in a condition that is not good for MEA, such as high temperature and low RH. An MEA decays much faster during an accelerated test, and could shorten the durability test from thousands of hours to hundreds of hours. If a regular durability test and an 

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R. Talreja, A damage mechanics based approach to durability assessment of composite materials, Composites and Finely Graded Materials, in ASME, Materials Division, vol. 80 ed. by T. Srinivasan et al. pp. 151-156 (1997)... 

Figure 12.23. Stress-time relationship for durability assessment.

The durability assessment may also inelude measurement of the response to inseet and fungal attaek. There would appear to be little inherent resistanee to these forms of attack beyond the eharaeteristies of the wood. A range of inseeticides and fungieides can be added. This is easiest if these ean be mixed with the adhesive system provided that resin performanee is not eompromised. The size of the partieles means that the seleeted material ean be distributed more easily within the panel. However inseet/fungal attaek usually does not beeome a factor unless the moisture content inereases, and it is this response that is most important. 

Rangaraj S. Durability assessment and modeling of wood-thermoplastic composites [dissertation]. Pullman (WA) School of Mechanical and Materials Engineering, Washington State University 1999. 

Despite some recent developments, the exploitation of the fitll potential for on-site bonded joints is mainly restrained at present by the lack of structural design guidance, standards for durability assessment and onsite acceptance testing. 

Procedures for the determination of important properties are essential for the selection of an appropriate product and for joint design and analysis. We have seen that adhesive polymers are sensitive to temperature and moisture, and to the rate at which stress is applied. Their bondline behaviour in joints depends greatly upon the system stiffness, and upon more subtle variations such as bondline thickness. It is therefore important that test methods are relevant to the real application, the fabrication conditions, the actual materials to be joined, and so on. Many standard test methods exist, for both strength and durability assessment, and these were discussed in Chapter 4. 

GaUocher SL. Durability assessment of polymer trileaflet heart valves. January 1, 2007 [FIU electronic theses and dissertations], http //digitalcommons.fiu.edu/dissertations/ AAI3299201. 

Mackay TG, Bernacca GM, Fisher AC, Hindle CS, Wheatley DJ. In vitro function and durability assessment of a novel polyurethane heart valve prosthesis. Artif Organs September 1996 20(9) 1017-25. 

Accelerated Durability Assessment of Composite Structures. ICCM 14, San Diego, 2003... 

D2918-99 Standard test method for durability assessment of adhesive joints stressed in peel... 

Table 9.1 Geotextile durability assessment tests (from CUR report 243 with ASTM International standards included)...

Figure 10.2 Laboratory weathering devices for exposed polymeric durability assessment.

For products that are covered by hENs, the specific durability assessment requirements are stated in Annex ZA of the standard, and the results of that durability assessment form part of the aforementioned CE marL... 

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