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Abstract

Adhesive bonding of fiber-reinforced plastic (FRP) panels usually results in undesirable surface deformation due to adhesive cure and thermal shrinkage. Bond-line-read-out (BLRO) refers to the fact that the bond line is visible on the panel surface opposite to the side of adhesive application. This paper studies the surface deformation on a bonded FRP structure which results from the differential thermal shrinkage between the panel material and the adhesive using the finite element method. Sheet molding compound (SMC) is chosen as a typical FRP material in the analysis. Three geometrical configurations are considered, namely, a bare adhesive film, an SMC backing strip, and an SMC hat section, respectively, bonded to the underside of an SMC flat plate. In particular, the effects of (1) material properties, (2) part geometry, and (3) adhesive thickness and coverage, on BLRO are investigated. Based on this study, it is concluded that BLRO can be reduced by the following means: (a) reducing the difference between the thermal expansion coefficients of SMC and adhesive, (b) lowering the adhesive-cure temperature, (c) increasing the SMC/adhesive Young's modulus ratio, (d) increasing the SMC plate/adhesive layer thickness ratio, (e) eliminating or reducing the adhesive squeezeout, and (f) if possible, modifying part geometry or bond line layout.

Keywords

bond-line-read-out finite element SMC adhesive bonding surface deformation

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References

1. Hersam, T. 1989. "Evaluation of Specific Variables Influencing Automotive Grade SMC Smoothness: Part I," 44th Annual Conference, Composites Institute, SPI, Session 12-A.

2. Wilson, E. L. and A. B. Isham . 1990. "Factors Affecting the Surface Smoothness of Automotive Body Panel SMC," 45th Annual Conference, Composites Institute, SPI, Session 1-A.

3. Kia, H. G. 1990. "Factors Affecting Rib Readout in Sheet Molding Compound Panels," 45th Annual Conference, Composites Institute, SPI, Session 1-B.

4. Rezanka, P. H. 1978. "Product Design Case Study: The 1977 Chevrolet Corvette Removable Roof Panels," 33rd Annual Conference, Composites Institute, SPI, Session 18-C.

5. Bence, I. J. , R. C. Bloom and E. Gray, Jr. 1981. "Design, Finite Modeling, and Structural Performance of a One-Piece SMC Auto Hood," 36th Annual Conference, Composites Institute, SPI, Session 21-E.

6. McClusky, J. M. and R. B. Jutte . 1983. "Development of SMC for Automotive Body Panel Use," 38th Annual Conference, Composites Institute, SPI, Session 1-A.

7. Lee, C.-C. 1989. "Surface Waviness and Observed Reflections-Mathematical Modeling for Various Inspection Methods," Proceedings of the Fifth Annual ASM/ESD Advanced Composites Conference and Exposition, pp. 175-185.

8. Melby, E. G. Unpublished research, GenCorp Research.

9. Gillespie, J. W., Jr. , R. L. McCullough , S. H. Munson-McGee , J. Garrett and B. Waibel . 1984. Composites Software Users Guide-SMC, University of Delaware.

10.

10. Wilson, E. L. , R. L. Taylor , W. P. Doherty and J. Ghaboussi . 1973. "Incompatible Displacement Models," in Nummerical and Computer Methods in Structural Mechanics, S. J. Fenves et al., ed., New York: Academic Press.

11.

11. Structural Dynamics Research Corporation . 1988. I-DEAS Manual, Model Solution and Optimization, pp. 5-45.

12.

12. Timoshenko, S. 1925. "Analysis of Bi-Metal Thermostats," J. Opt. Soc. Am., 2:233-255.

13.

13. Chen, J. S., GenCorp Research, personal communication.

14.

14. Ross, P. M. 1976. "Development of a Light Weight Plastic Hood Panel for High Volume Passenger Car Applications," 31st Annual Conference, Composites Institute, SPI, Session 11-A.

A Finite Element Study of Bond-Line-Read-Out

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