The Influence of Preparing Method on Novel X-Truss/Foam Sandwich Structure

Abstract

Novel X-truss/foam sandwich structures were prepared by Z-pin inserted and bias stitching method, respectively, in order to improve the transverse mechanical behavior. With such reinforcements, the collapse resistance capability of the core and the bonding strength between the core and the skins are obviously increased. Thus the principal disadvantages of conventional sandwich structures are solved. The Z-pins and stitches embedding in rigid polyurethane foam configured a truss, which was made of carbon fiber/epoxy resin. The architectures of specimens made from Z-pin inserted and bias stitching methods are very similar but not identical, which make their mechanical performances different from each other. In order to evaluate these two methods, out-of-plane mechanical tests, such as compression, shear, and tension were practiced and failure modes were compared. In some conditions, the specimens made from the Z-pin inserted process have a higher compression modulus, but a lower tension and shear strength compared to that made from the bias stitching process. Moreover, there are big differences in their failure modes.

Mechanical Performance of X-Truss/Foam Sandwich Construction

“…In this study, X-truss/foam sandwich panels were prepared as described in the previous study [20]. Z-pins with diameters of 1.0 and 0.48 mm were manufactured from carbon fiber of 12 and 3 K yarn, respectively, with a matrix of phenolic epoxy resin cured by BF 3 -monoethylamine complex at 1408C for 1 h and 1808C for 2 h. The structure parameters of the X-truss/foam sandwich panel were defined as in Figure 1.…”

“…The experimental fixtures and mechanical property calculation methods have been presented in detail in Ref. [20]. In addition, an overhanging beam three-point bending test, as shown in Figure 3, was conducted to measure the sandwich flexural stiffness in accordance with the GB/T 1456-2005 standard on a specimen of 400 Â 60 mm, where ¼ 200 mm and ¼ 90 mm.…”

“…Usually, the X-truss/foam sandwich construction can be prepared with Z-pin inserted or bias stitching methods. The preparing processes and their characteristics have been discussed in our previous study [20]. The aim of this study is to give a detailed investigation of the influence of structure parameters on sandwich mechanical performance, where the X-truss/foam sandwich was prepared by the Z-pin inserted process.…”

Thermal Expansion Process for Manufacturing of Stitched Sandwich Structures

“…Due to compressive distortion, the stitches relaxed and buckled to some extent before curing. When compared with straight stitches, the reinforcing efficiency of buckled stitches is less with the same increase of structure mass [15].…”

Effect of Core Architecture on Charpy Impact and Compression Properties of Tufted Sandwich Structural Composites

“…May-Pat et al used the conventional relations of equivalent series-parallel springs to estimate the compressive and shear properties of sandwiches and analyzed the weight gain caused by the massive absorbed resin [20]. Jijun et al [21] fabricated a novel X-Truss/foam sandwich structure with Z-pins inserted and bias stitching, and the compression test was conducted to evaluate these two methods. The results indicated that the specimens made from the Z-pin process have a higher compression modulus Polymers 2021, 13, 1665 2 of 11 compared to those made with bias stitching.…”