BlakMax; I initially thought you had misread, or simply missed, large parts of the content in the links. However, having looked at the papers you linked to it then became apparent that whilst you might have had some insight and experience that would have been uncommon back in the 80s, you appear to have buried your head in the sand for a couple of decades only to re-emerge now whilst failing to grasp that, amongst other things, the fields of adhesion, fracture mechanics, adhesives, computing, numerical methods, etc… have changed dramatically over the decades that have past. Most obviously, you appear to think that knowledge of the need for surface treatment of substrates prior to adhesive bonding is some sort of expertise when in today’s day and age it is common knowledge within the relevant fields; a whole range of methods for many substrates, environments, etc.. are openly described and available on the internet and these are also matters your adhesive and/or substrate supplier will likely be able to advise on (for free) through their technical sales support or on-line documentation and application guidance resources, e.g;
LinkLink
blakmax said:
‘Had a look at the link adfergusson provided, and I immediately dismissed the work’
Well the you’d better avoid getting in any modern car as the approach described by Ambrose (Disclosure; Ambrose and I co-supervise some work together at Imperial College) in the first is the basis for the design methodology for structural epoxy adhesives used in most cars. These design techniques were developed by members of the adhesives group at Imperial College, including Tony Kinloch and Gordon Williams (both Fellows of the Royal Society with Tony holding the position of Chair of Adhesion) and first used in Lotus’ bonded chassis.
blakmax said:
‘ If anyone believes that they can assess the performance of adhesive bonds which use grit-blast and solvent degrease as the complete surface preparation they are sadly mistaken,’
You seem to imply that I, or the document in the link, am suggesting that this alone is acceptable? If you actually looked at Ambrose’s document (which is now twenty years old) then you’d have seen it that the work involves comparing the fatigue life of joints with different surface treatments tested in dry and immersed in water (with comments on water diffusion rates).
blakmax said:
I don't care how great the mathematics is
That documents sticks to mode 1 testing as the mechanics behind this load state is comparatively simple; the maths contained therein are limited to first order differentiation and integration. If you want to do an Engineering degree in the UK then you need to be able to solve these sorts of equations whilst you are still in high school. You propose on your adhesion associates website that you have some special blend of analytical solutions that allow you to accurately predict joint performance; given that all but the most very basic load states in components made of only one material can be reduced to one dimensional problems, or ‘great mathematics’ as you might call it, how the hell do you go about dealing with real world structures where the stress states require description through higher order partial differential equations?! Or, in addition to fracture mechanics, do you not believe in Hooke’s law and the general framework of elasticity either?
blakmax said:
Hence, the result obtained from ANY mechanical test will depend totally upon the extent of hydration that has occurred at the time the specimen is tested.
Yeah, sure, the mechanical and thermal properties of the adhesive and substrate have no bearing…. nonsense…... just utter nonsense. Unless that is (as blakmax appears to) you come from a time and place where the idea of doing (now antiquated) surface treatments such as a chromic acid etch or anodization would be thought some unusual novelty.
blakmax said:
cohesion where the adhesive fractures and adhesion where the failure propagates along the interface. In between these extremes, there is mixed-mode failure
I noticed that you cited one of Tony Kinloch’s book (Kinlock, A.J., Adhesion and Adhesives, Chapman and Hall ltd, New York, 1987, pp. 78.); was page 78 the only page you read? Other parts of the book discuss mixed mode behaviour. Mixed mode behaviour in the context of the adhesives (and composites) community is understood by pretty much everyone, but you, to mean the proportion of the stress state at a crack that is mode 1, 2 or 3. You appear to have some bizarre little convention of your own but, for example, the book of Tony’s that you cite has been cited 2181 times (
https://scholar.google.co.uk/citations?user=bXUqSnEAAAAJ&hl=en) and the nature of mixed mode failure is described in there as the ratio of stress components at a crack tip. Additionally, I’ve never come across someone describe/misunderstand mixed mode fracture behaviour in the way you have; perhaps this is why the only person who seems to cite your publications is yourself? If I am wrong then please point me to a peer reviewed journal paper where this description of mixed mode behaviour has been accepted.
blakmax said:
It is far more productive to ensure that the bonding process prevents hydration, and I can assure readers that grit-blast and solvent clean can never prevent hydration on most metals.
This is such a well-known ( I was introduced to the subject in the second year of my UG degree) issue these days and loads of companies have standard processes off the shelf solutions for most scenarios . Adampar; I suggest you make contact with your local adhesive supplier and/or speak to small scale MROs around your local airfield/airport in your area who can advise you on companies that can carry out etching or anodising suitable to your substrates. Now-a-days there are also alternatives to these unpleasant processes that rely on relatively benign chemistry, like functionalised silane and siloxane chemistry that are also highly resistant to moisutre and passivate substrate surfaces from hydration. Blakmax would probably be horrified by these too (even if the likes of Airbus, Boeing, Rolls- Royce, etc.. use surface treatments like these) as some of them are water based colloids
