The Experts below are selected from a list of 39204 Experts worldwide ranked by ideXlab platform

Xuewu Fan - One of the best experts on this subject based on the ideXlab platform.

  • ultra thin carbon Fiber mirrors nickel plated optical fabrication and thermal deformation test
    Optik, 2019
    Co-Authors: Yongjie Xie, Yongjie Wang, Jiaoteng Ding, Xuewu Fan
    Abstract:

    Abstract The aperture of space remote sensing camera is increasing, and the demand for lighter weight is getting higher and higher. With the advancement of active optics, the thickness of optical components has gradually grown to light and thin. It is extremely difficult to develop ultrathin mirrors using brittle Materials such as traditional optical glass and silicon carbide. Due to advantages such as low density, high specific stiffness, low thermal expansion coefficient, toughness, and additive rapid manufacturing properties, carbon Fiber reinforced plastic (CFRP) is one of potential applications for large-diameter ultra-thin mirrors. However, the carbon Fiber Composite Material is a two-phase Material that cannot be used as optical surface and must be surface-modified. In this paper, the surface modification of CFRP substrate was carried out by chemical nickel plating and nickel electroplating. The modified nickel layer covers all surfaces of CFRP substrate, and nickel layers satisfying the thickness, bonding force, and internal stress requirements. A Φ100 mm aperture ultra-thin carbon Fiber mirror developed, after optical fabricating, its surface accuracy RMS is better than λ/15. Thermal deformation analysis and test show that the thermal deformation of ultra-thin carbon Fiber mirrors is mainly manifested by the change of radius of curvature, which is caused by the thickness error of the nickel layer on the front and rear faces. In addition, although thermal deformation caused by the lamination angle error of CFRP substrate is relatively small in value, it should still be given enough attention, because the astigmatic error produced is hard to eliminate.

Fan Xuewu - One of the best experts on this subject based on the ideXlab platform.

  • Ultra-thin carbon Fiber mirrors: nickel plated, optical fabrication and thermal deformation test
    Elsevier GmbH, 2019
    Co-Authors: Xu Liang, Xie Yongjie, Wang Yongjie, Ding Jiaoteng, Ma Zhen, Fan Xuewu
    Abstract:

    The aperture of space remote sensing camera is increasing, and the demand for lighter weight is getting higher and higher. With the advancement of active optics, the thickness of optical components has gradually grown to light and thin. It is extremely difficult to develop ultrathin mirrors using brittle Materials such as traditional optical glass and silicon carbide. Due to advantages such as low density, high specific stiffness, low thermal expansion coefficient, toughness, and additive rapid manufacturing properties, carbon Fiber reinforced plastic (CFRP) is one of potential applications for large-diameter ultra-thin mirrors. However, the carbon Fiber Composite Material is a two-phase Material that cannot be used as optical surface and must be surface-modified. In this paper, the surface modification of CFRP substrate was carried out by chemical nickel plating and nickel electroplating. The modified nickel layer covers all surfaces of CFRP substrate, and nickel layers satisfying the thickness, bonding force, and internal stress requirements. A Φ100 mm aperture ultra-thin carbon Fiber mirror developed, after optical fabricating, its surface accuracy RMS is better than λ/15. Thermal deformation analysis and test show that the thermal deformation of ultra-thin carbon Fiber mirrors is mainly manifested by the change of radius of curvature, which is caused by the thickness error of the nickel layer on the front and rear faces. In addition, although thermal deformation caused by the lamination angle error of CFRP substrate is relatively small in value, it should still be given enough attention, because the astigmatic error produced is hard to eliminate. © 2018 Elsevier GmbH

Karl Englund - One of the best experts on this subject based on the ideXlab platform.

  • field performance evaluation of pervious concrete pavement reinforced with novel discrete reinforcement
    Case Studies in Construction Materials, 2019
    Co-Authors: Othman Alshareedah, Somayeh Nassiri, Zhao Chen, Karl Englund, Hui Li, Osama Fakron
    Abstract:

    Abstract Pervious concrete (PC) pavements are used for stormwater management and flood mitigation. However, the highly porous macrostructure of PC results in low mechanical properties compared to portland cement concrete (PCC). Cured Carbon Fiber Composite Material (CCFCM) is heavily used in manufacturing of high-performance products. Therefore, large quantities of excess CCFCM Materials are generated, requiring proper disposal and reuse applications. In this study, recycled CCFCM were used as discrete structural reinforcement in a PC pavement demonstration project. In addition to one Control section, two pavement sections were paved using PC mixed with 0.27 and 0.40% volume fractions of CCFCM, respectively. Field cores and cast specimens from CCFCM-PC mixes achieved similar 7 and 28-day flexural, tensile, and compressive strengths to the Control, although their porosity was higher. Furthermore, CCFCM-PC sections had higher infiltration rates than the Control. Using lightweight deflectometer load testing, CCFCM-PC pavement sections showed lower surface deflection than the Control under the same applied load. Based on these findings, CCFCM was successfully implemented as reinforcing elements in PC, providing an environmentally-friendly solution to recycle this Material.

  • using carbon Fiber Composites for reinforcing pervious concrete
    Construction and Building Materials, 2016
    Co-Authors: Milena Rangelov, Somayeh Nassiri, Liv Haselbach, Karl Englund
    Abstract:

    Abstract Pervious concrete (PC) pavement applications are growing in popularity due to the environmental and stormwater management benefits that PC can offer. However, relatively low mechanical properties and durability of PC, comparing to conventional Portland cement concrete (PCC), limit its use for vehicular applications. In this study, different size fractions of cured carbon Fiber Composite Material (CCFCM) pieces were incorporated into a PC mixture (rPC) in three volume fractions. The goal was to determine the physical and mechanical properties of rPC in comparison to the corresponding properties of plain PC (control). Seven mixture designs were prepared in order to investigate the effect of CCFCM volume fractions as well as CCFCM particle sizes. The test results indicated that CCFCM addition enhanced the workability of the PC mixtures. rPC mixtures presented higher average infiltration rates when compared to the control mixture. Improvements in mechanical properties were seen on 28-day compressive strength (4–11%), 7-day tensile strength (11–46%) and in modulus of elasticity (6–45%). In terms of resistance to mass loss in Cantabro and surface abrasion, rPC mixtures presented various behaviors, with one mixture containing the highest volume fraction and a combined size fraction, outperforming the control in both tests. Overall, the results of this study indicate that incorporation of CCFCM is promising in improving physical and mechanical properties of PC.

Hyun Surk Kim - One of the best experts on this subject based on the ideXlab platform.

  • damping improvement of machine tool columns with polymer matrix Fiber Composite Material
    Composite Structures, 1998
    Co-Authors: Dai Gil Lee, Seunghwan Chang, Hyun Surk Kim
    Abstract:

    In order to improve the damping capacity of the column of a percision mirror surface grinding machine tool, a hybrid column was manufactured by adhesively bonding glass Fiber reinforced epoxy Composite plates to a cast iron column. To optimize the damping capacity of the hybrid column, the damping capacity of the hybrid column was calculated with respect to the Fiber orientation and thickness of the Composite laminate plate and compared to the measured damping capacity. From experiments, it was found that the damping capacity of the hybrid column was 35% higher than that of the cast iron column.

Rüdiger Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • Modeling and simulation of macro-Fiber Composite layered smart structures
    Composite Structures, 2015
    Co-Authors: Shu-hai Zhang, Rüdiger Schmidt, Shun-qi Zhang, Ya-xi Li, Yan Li, Rüdiger Schmidt
    Abstract:

    Piezo Fiber Composite Material, macro-Fiber Composite (MFC), is increasingly applied in engineering, due to its high flexibility and strong actuation forces. This paper develops a linear electro-mechanically coupled finite element (FE) model for Composite laminated thin-walled smart structures bonded with orthotropic MFCs having arbitrary piezo Fiber orientation. Two types of MFCs are considered, namely, MFC-d31 in which the d31 effect dominates the actuation forces, and MFC-d33 which mainly uses the d33 effect. The FE model is developed based on the Reissner-Mindlin hypothesis using linear piezoelectric constitutive equations. The present results are compared with ANSYS and experimental results reported in the literature (Bowen et al., 2011). Afterwards, isotropic or Composite structures with cross-ply laminates, integrated with MFC-d31 or -d33 patches having different Fiber orientation, are simulated under a certain electric voltage on the MFC patches.