Out-of-Plane Deformation due to the Ply Angle Misalignment in CFRP Laminates (The Effect of the Stacking Sequence on Thermal Deformation)

Abstract

Strict geometrical stability is required for the precise structures like telescopes. Unpredictable out-of-plane deformation is a serious problem when we use CFRP (Carbon Fiber Reinforced Plastic) laminate to the precise structure. This out-of plane deformation of symmetrical CFRP laminate mainly arise from combination effects of ply angle misalignment and temperature change. We discussed here is effective stacking sequence of CFRP laminate that mitigate the deformation caused by the ply angle misalignment. The analysis based on laminate theory was performed to calculate the thermal deformation. In this analysis, the random numbers were added to each layers as ply angle misalignments. The analytical results were obtained statistically by Monte Carlo method. Mohr's curvature circle was also incorporated to evaluate the deformation as P-V (peak to Valley) values. We performed the analysis with various stacking sequence. It was calculated that the symmetric cross-ply laminates deformed 10 times larger than the other quasi-symmetric laminates. In the case of the total ply number is less than 12, the stacking sequence in the laminate has a significant effects on the thermal deformation. However, if the total number ply number is more than 24, effect of stacking sequence on the thermal deformation becomes negligible. We also discussed the geometrical stability of CFRP mirror by considering unavoidable ply angle misalignment. It was presumed that the CFRP mirror can be used for wide range of wave length when the back structure was attached to CFRP laminates.

Dimensional stability of epoxy-based and cyanate-based carbon fiber-reinforced plastics

“…The moisture content of CF/cyanate was 50% of that of CF/epoxy and moisture-induced strain was 25%, which means that CF/cyanate has excellent moisture resistance. The maximum moisture content M m was assumed to be the moisture content when t ¼ 2000 h. Diffusivity can be determined using equation (9). At initial stage of moisture absorption (M/M m < 0.5), the moisture content was in proportion to square root of time for each specimen.…”

“…19 Equations ( 9) and ( 10) can be used to describe moisture absorption behavior. From the initial slop in Figure (M/M m < 0.5), diffusivity of CF/epoxy and CF/cyanate were obtained by fitting calculated results using equation (9). CME were also determined based on the results shown in Figure 8(a) and (b), and the results are listed in Table 3.…”

“…In previous studies, we suggested methods of designing geometrically stable CFRP laminates by considering the plyangle misalignment during the stacking process. [7][8][9] Controlling the ply angle exactly is quite difficult. It was observed that standard deviation of 0.4 of plyangle misalignment exists for each laminate.…”

“…7 The outof-plane thermal deformation of a quasi-isotropic laminate with ply-angle misalignment was calculated in order to evaluate the performance of CFRP laminates as a geometrically stable precise optical mirror. [8][9][10] Thus, an effective method of designing CFRPs that takes thermal deformation into account was developed. Moreover, investigations on time-dependent deformations such as the deformation induced by moisture absorption and that caused by internal thermal residual stress have also been conducted.…”