Thermal deformation generated on a CFRP laminated reflector

Abstract

Carbon Fiber Reinforced Plastic (CFRP) has high specific stiffness and its thermal deformation can be controlled by fiber orientation. Therefore, it is often adopted as a material of space observation systems. In this study, experiment, numerical and analytical calculation on thermal deformation of CFRP reflector models were conducted to investigate the characteristics of thermal deformation of CFRP reflectors (mirrors) for space observation systems. Two types of reflector models were manufactured, which were comprised of a quasi-isotropic CFRP laminate with and without an sprayed aluminum layer and a polyurethane layer on the top surface. The experimental results showed that the out-of-plane thermal deformation of the reflector model with the aluminum and polyurethane layers is considerably larger than that of the reflector model without the aluminum and polyurethane layers and maximum and minimum displacement were observed in specific directions. The result of the numerical calculation showed the same trend. Additionally, this trend was discussed analytically. Moreover, uncertainty of the structure and method of reducing out-of-plane displacement were discussed. When shape control to suppress thermal deformation of CFRP reflectors is considered, the result obtained in this work is important to determine the optimal placement of actuators.

Quantitative Investigations on the Dimensional Stability of a CFRP Reflector Model against Temperature Variations

“…In a previous study, the authors observed the out-of-plane thermal deformation of a reflector model composed of quasiisotropic CFRP laminate (XN60/NM31, Sanki Composite Co.). 10) The stacking sequence was ½0=À45=90=45 s . The appearance and dimensions of the reflector model are described in Fig.…”

“…In a previous study, thermal deformation of a reflector model comprising a CFRP laminate was observed, and the extent of the out-of-plane thermal deformation was found to be non-negligible. 10) In addition, a finite-element analysis was performed in a previous study, and the error in the fiber orientation angle when laminating prepregs was found to be a significant cause of the out-of-plane thermal deformation of CFRP reflectors. 11) The authors of the previous study also investigated the suppression of a representative mode of the out-of-plane thermal deformation of a CFRP reflector model due to fiber orientation errors by applying ex-ternal forces with linear actuators.…”

“…Observed out-of-plane thermal deformation of the CFRP reflector model (stacking sequence: ½0=À45=90=45 s ) 10). …”

Suppression of Out-of-Plane Thermal Deformation of CFRP Reflectors by Linear Actuators

“…In the previous studies, the present authors studied thermal deformation of reflectors experimentally and analytically. 5,6) As a result, it was shown that surface coating which is essential to improve electric conductivity of the surface and the existence of error of carbon fiber orientation angle cause non-negligible out-of-plane thermal deformation. Therefore, to realize spacebased CFRP reflectors, suppression of the out-of-plane thermal deformation is essential.…”

“…As mentioned before, to realize space-based CFRP reflectors, suppression of the out-of-plane thermal deformation is essential. Thus, in this paper, the present authors investigated the optimal location of actuators to suppress the out-of-plane thermal deformation caused by the existence of surface coating and the fiber orientation error 5,6) by several linear actuators. Additionally, moving the reflector models themselves rigidly, that is, defocusing was also introduced and optimal value of defocus was sought.…”