Damage evaluation of quartz woven fabrics during needle punching process

Abstract

This paper reports an experimental study on the damage evaluation of quartz woven fabrics during needle punching process under different needle punching densities. The straight fiber bundles begin appearing in Z direction at 50 punches · cm−2 and the “U-shaped” fiber bundles begin being observed at 210 punches · cm−2. The retention ratio of mean breaking force (RRMF) of the needle-punched quarts woven fabrics in warp direction decreases from 100% to 49.4% with an increase in needle punching density from 0 to 10 punches · cm−2, and that in weft direction decreases from 100% to 50.21% with the same increments in needle punching density, but the RRMF in warp direction decreases from 49.4% to 0.35% when the needle punching density increases from 10 to 245 punches · cm−2 and that in weft direction decreases from 50.21% to 0.19% with the same increments in needle punching density; obviously, the initial needle punching density increments (0 to 10 punches · cm−2) seem to have weakened tensile property more significantly compared with needle punching density increments from 10 to 245 punches · cm−2. The retention ratios in warp and weft directions are 0.61% and 0.34%, respectively, at 210 punches · cm−2, which are roughly equal with those at 245 punches · cm−2. Therefore, it could be concluded that the tensile property has reached the minimized at 245 punches · cm−2. In addition, there is an obvious paired similarity existing in the macro damage morphologies, the load–displacement curve trend at the adjacent needle punching density from 70 to 245 punches · cm−2 in 35 punches · cm−2 increments, also such similarity exists when the needle punching density is at 10 to 60 punches · cm−2.

Numerical and experimental analysis on anisotropic thermal conductivity of carding quartz fiber web based on the reconstruction model

“…As a result of its low mass, high strength 1 and excellent thermostability, 2 carding quartz fiber webs (CQFWs) 3,4 have been widely used in making engineer nozzles (as shown in Figure 1), equipment of thermal protection, radomes of the radar and missiles. [5][6][7] Moreover, thermal conductivity plays an essential role in determining structure failure and service life of the structural parts above. [5][6][7][8][9] Therefore, carrying out the experimental and numerical analysis on the anisotropic thermal conductivity (ATC) and the detailed anisotropic heat transmission (AHT) of the CQFW is of great significance to the property design, manufacture of the CQFW and its composites.…”

“…[5][6][7] Moreover, thermal conductivity plays an essential role in determining structure failure and service life of the structural parts above. [5][6][7][8][9] Therefore, carrying out the experimental and numerical analysis on the anisotropic thermal conductivity (ATC) and the detailed anisotropic heat transmission (AHT) of the CQFW is of great significance to the property design, manufacture of the CQFW and its composites.…”