Adhesive bond joints for

Figure 3.3 Adhesion strength of the adhesive-bonded joints for different relationships of the normal and tangential stresses 100 days after cementing (1) unloaded specimens (2) shear load 0.3 GPa (3) normal load 0.36 GPa.

The value of 6ic can be used not only as a comparative but also tis an estimated characteristic of the cracking resistance of adhesive-bonded joints. For this purpose it is necessary to find a relationship between the displacements 6i, load, body geometry, and crack length. The relationship for a crack with yield zone localized within its plane can be written... 

Determining thermal internal stresses. Experimentally, the stress with a particular temperature change is determined by the deflection of the free end of the cemented three-layer plate fixed as a cantilever. The deflection of the plate end was determined by means of a projection optical system. Figure 4.3 displays the distribution of the thermal internal stresses in a Sprut-5M adhesive-bonded joint for temperature change from 20 to 42°C. Plates made of IKhlSNlOT steel 0.07 mm thick and aluminum foil 0.02 mm thick were used as substrates. It is evident that the internal stresses are characterized by maximum values on the interfaces. 

Deb A, Malvade I, Biswas P and Schroeder J (2008), An experimental and analytical study of the mechanical behaviour of adhesively bonded joints for variable extension rates and temperatures , Int J Adhes Adhes, 28(1-2), 1-15. 

It has been shown that a very simple approach can be used for predicting the lap shear strength of adhesively bonded Joints for ductile adherends and ductile adhesives. However, it cannot take into account such more complex situations as thermal stresses or changes in adherend thickness (stepped or tapered joints). 

Hart-Smith, L. J. (1978b) Adhesive-bonded joints for composites— phenomeno-logical considerations, McDonnell-Douglas Co. Paper 6707, Technology Confs. Assoc. Conf. on Advanced Composites Technology, El Segundo, California. 

Sealants are often applied to the edges of adhesively bonded joints for prevention of water ingress into the joint. The sealant sometimes can be the same material... 

Munns, G.A. Georgiou, Non-destructive testing methods for adhesively bonded joint nspection - a review, INSIGHT, Vol 37, No 12, Dec 1995, pp 941-952... 

When the scanning of the adhesive bonded joint between the shells on the leading edge is complete, the rotor blade is rotated 180° and another special designed Y-module is applied for inspection of the trailing edge of the rotor blade in set-up 3, illustrated on figure 5. 

The best approach to achieving good performance in bonded joints is to select the proper adhesive, design the joint properly for the specific application, and maintain rigid process control. One disadvantage in the use of adhesives is the absence of good non-destructive tests to determine the strength of adhesive-bonded joints in a wide variety of ord applications... 

The effect of alkoxide primers on crack propagation in the adhesively bonded joints is shown in Figs 1-5. The effect of alkoxide primer on crack propagation for PES-bonded steel primed at 34% RH and tested by immersion in DI water at 100°C for 200 h is illustrated in Fig. 1, plotted as crack length (in cm) vs. time (in h). The initial crack length for both the A1TSB and AITTB primed samples was... 

Atmospheric Exposure of Adhesive Bonded Joint and Structures, Recommended Practice for D 1828... 

Pipe and Pipe Fittings, Adhesive Bonded Joint Type, for Aviation Jet Turbine Fuel Lines... 

Landrock, A.H., Effects of Varying Processing Parameters in the Fabrication of Adhesive Bonded Joints, Part XVIII, "Adhesive Bonding and Related Joining Methods for Structural Plastics—Literature Survey," Picatinny Arsenal Technical Report 4424 (November 1972). 

Thus, independent of the dimensions of the test pieces, the strength values obtained are always comparable. These relationships refer also to bonded joints for which the term adhesive strength has become established for destructive testing of overlapped test pieces (Figure 10.2). It is abbreviated by the Greek letter r (pronounced tau) referenced with the index B ... 

This rule refers to circular bonded joints, for example, tubular bonded joints or shaft-hub joints, with heat or hot-curing reactive adhesives, if different metal materials are to be bonded, Figure 11.5. 

ASTM Standard D 5266, Standard Practice for Estimating the Percentage of Wood Failure in Adhesive Bonded Joints, ASTM International. West Conshohocken, PA, June 1999. 

The fracture-based approach derives from continuum fracture mechanics theory, which claims the strength of most real solids is governed by flaws within the material [2]. To help predict this type of behavior, many test methods have been developed to determine fracture properties of adhesives. These tests are used to characterize the mode I, II, and III fracture properties of many types of material systems. In this study, the focus will be on the mode I and II characteristics of bonded joints for automotive applications. 

Munns. 1. J.. and Georgiou. G. A. (1995). Non-destructive testing methods for adhesively bonded joint in.spection--A review. Insight. Dec. 1995. 12. 941 9.S2. 

Other environmental related tests include ASTM D-904, Standard Practice for Exposure of Adhesive Specimens to Artificial (Carbon-Arc Type) and Natural Light ASTM D-1828, Standard Practice for Atmospheric Exposure of Adhesive-Bonded Joints and Structures ASTM D-1879, Standard Practice for Exposure of Adhesive Specimens to High Energy Radiation and ASTM D-3310, Standard Test Methods for Determining Corrosivity of Adhesive Materials. 

G. P. Anderson, S. Chandapeta, and K. L. DeVries, in Adhesively Bonded Joints Testing, Analysis, and Design, ASTM STP-981 (W. S. Johnson, ed.), American Society for Testing and Materials, Philadelphia, 1988. 

The reason for the lack of concordance between the theoretically and experimentally determined values of the adhesion strength lies in the fact that the process of achieving high adhesion strength is hindered by a number of phenomena that accompany the formation of adhesive-bonded joints. These factors that decrease the strength of adhesive-bonded joints can be divided into two groups ... 

With vacuum treatment of the specimens (at 200°C, 103 Pa) for 10 days, the content of the monomer in the adhesive layer decreased and the adhesion strength increased. The character of adhesion failure of the joint changed to cohesive type. The data allow a more complete explanation of the so-called latent period— the period of achieving the maximum adhesion strength. It is evident that the strengthening of some adhesive-bonded joints in the course of time is caused by volati-... 

In many cases precision methods allowed detection of the thin layer of adhesive on the substrate surface [37—39]. For example, using disturbed total internal reflection it was shown [40] that when polyethylene was peeled off the quartz a thin layer of the polymer remained on the latter. The remnants of the polyethylene are completely washed off the quartz by xylene, which is proof of the absence of interaction between the quartz and the polyethylene. Such disintegration of adhesive-bonded joints is determined both by the adhesion interaction between the polymer and the substrate and by differences between the behavior of the polymer when in thin layers on the substrate and when in the free state [85—89]. 

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