The application of adhesive bonding technology of composite materials began in the aerospace field in the early days. With the continuous expansion of the application field of advanced composite materials, these new materials and technologies are now more and more widely used in the field of civilian products production. There are two technical focal points in the structure design of composite material bonding technology. One is that the strength of the bonding part is greater than the failure strength of the matrix part of the material. The other is the reliability of the long-term application of the adhesive part. In the field of pressure vessel applications, the United States boiler and pressurized container specification(ASME), which represents the highest level of application in the world, can be applied to nuclear power equipment. The standard proposed is that the blasting pressure of the material should be greater than 6 times the rated working pressure; The standard proposed in terms of performance reliability is rated pressure-zero pressure-rated work pressure .... such a alternating pressure is repeatedly applied to the pressure vessel to test the reliability of the pressure vessel. Today's composite bonding technology has developed to a very high level, from aerospace to God and God, can see their application. There are examples of the application of composite bonding structures in advanced international standards. For example, in the "FRP Pipeline Manual" issued by the United States Plastics Industry Association(SPI), in the "FRP Pipeline Manual", in the connection system chapter, The application of adhesive structure has been standardized. With regard to the bonding structure, it has already been applied in the winding process. In the winding process, when making high pressure thick wall pipes, thick wall pipes are not completed in one winding molding, but completed by secondary winding molding. During the secondary winding molding, a layer of resin must be coated on the outer wall of the once wound, and then the secondary winding is formed. The primary winding layer and the secondary winding layer are essentially glued together. The pressure film shell produced by our company adopts the adhesive structure on the combination of the straight pipe and the end head. The performance test of the adhesive layer is verified by the ASME specification. In the design of adhesive strength, our design principle is that the adhesive strength of the adhesive structure is greater than the axial force generated by 6 times the rated working pressure, ie:
Σ b.S & GT; 6π R2. P
Σ B-shear strength of the adhesive joint;
S-adhesive area
R-membrane shell radius;
P-membrane shell rated working pressure
In the test of mechanical properties of adhesive structure, we used two kinds of test items to verify. First, the mechanical properties of short-term membrane shell under 6 times working pressure; The second is to use 1.5 times the working pressure -- zero pressure -- 1.5 times the working pressure -- for a long time. Such a alternating pressure repeatedly acts on the membrane shell to detect the reliability of mechanical properties.
The FRP pressure film shell produced by our company has a high cost performance, and the product quality specification is formulated according to the ASME standard. A large number of experiments and explorations have been carried out on the bonding technology, and certain results have been achieved. In the future, it is also expected that adhesive technology will be applied to other developed products.
