Bond area

The bonding area rate in the bonding process can be presumed from the height of the echo. 

The reverse of the phase is shown that the bonding area rate became 80% or more, as the ultrasonic wave of incidence from the titanium side. 

The scanner has been constructed in modules which, for future applications, makes it easy to increase the length of the scanner for inspection of larger blades, by adding further modules to the system. In co-operation with LM Glasfiber and RIS0 it was decided to construct the first scatmer for inspection of blades with a length of max. 21m. In order to be able to scan primarily the bonded areas from the root to the tip of the rotor blade, a so-called X-unit module was constructed. The movement from the root to the tip of the blade was controlled by the P-scan system. 

Fig. 4 Y-module positioned for set-up 2, for inspection of bonded areas on the leading edge.

Another variant of the friction welding process, linear friction welding, uses servo-hydrauHcs pumps to vibrate parts back and forth against each other. Bond areas of approximately 1000 mm can be joined the attachment of turbine blades to rotors is a prevalent apphcation of this technology. 

Radiographic. Radiography is an exceUent nondestmctive test (NDT) method for evaluating the bond of Al—steel electrical and Al—Al—steel stmctural transition joints. It provides the capabiHty of precisely and accurately defining all nonbond and flat-bond areas of the Al—steel interface, regardless of size or location (see Surface and interface analysis). 

Maturation as a technology does not mean that advancement and innovation has ceased. Adhesive bonding is so essential to the aerospace field that as long as there is a desire to go higher, faster and farther more efficiently, there will be an incentive to develop new materials and processes for adhesive bonding. Areas of particular interest for future applications are high-temperature adhesives, fiber-reinforced metal laminates and more efficient bond assembly techniques. 

It is obvious that the response to tensile forces applied on each of the principle directions will be different due to the orientation of the fibre segments and of the bonded areas connecting them. Forces acting on a hypothetical diamond-shaped portion of the fibre net-... 

Adsorption might be expected to create additional fibre-to-fibre bonds and/or to strengthen existing bonds, but there is evidence that the increase in tensile strength of paper is caused primarily by an increase in the bond strength per unit of optically bonded area, rather than by an increase in the extent of the relative bonded area itself (Figure 7.13). 

Figure 7.13 Effect of cationic starch on the relationship between tensile strength and relative bonded area.

A series of delamination rate tests were conducted on the Chemlok 205/220 adhesive system. The test specimen was developed from a modification of the standard (ASTM D-429) peel test. Each specimen had two one inch square bond areas on a monel substrate. 

The local energy density H(r) in the bonding area is defined by equation 682,83 ... 

There was previously a separate ISO standard for adhesion in shear but this was withdrawn in favour of extending the standard for shear modulus to allow the test to be continued to the failure point, i.e. the two methods have been combined. The composite method is contained in ISO 182715 and uses the same quadruple element test piece as did the separate adhesion standard. The double sandwich construction is intended to provide a very stiff test piece which will remain in alignment under high stresses. The present standard quadruple test piece uses rubber elements 4 1 mm thick and 20 5 mm long and these tolerances are much less tight than previously. The measured adhesion strength in shear is less affected by the test piece shape factor then tension tests8 and the wider tolerances should be perfectly satisfactory. The test piece is strained at a rate of 50 mm/min, in line with the speed for most other adhesion to metal tests, and the result expressed as the maximum force divided by the total bonded area of one of the double sandwiches. The British equivalent BS 903 Part A 1416 is identical. 

All manifestations of early attack on the cotton fiber are compatible with the interpretation that it is the Cx enzymes that initiate the attack. This is true whether it is fragmentation into short fibers (16,39), increase in the uptake of alkali (S factor) (16,26), or loss in tensile strength (16). It is possible that some of these early changes may reflect action only on a very small portion of the fiber, such as the amorphous or less orderly hydrogen bonded areas, the primary wall (44), or the areas of structural weakness that are reported to traverse the whole cell wall (45). At the same time, there must be some significance in the fact that it is, in the main, only the Cx enzymes that produce changes detectable by these methods. 

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