Development and Evaluation of Stitched Sandwich Structures

计划进行一项探索性研究计划，以开发和评估复合材料夹层结构的厚度缝合。我们将探讨用芳纶纱线缝合泡沫塑料夹芯板的可行性和潜在的好处。为了提供低成本的制造，我们建议使用低成本、非高压罐工艺来制造缝合的夹芯板。夹芯板将在干燥状态下缝合，真空装袋，并使用真空辅助树脂转移模塑(VARTM)工艺进行渗透。贯穿厚度的缝合将为靠近工具表面的面片提供树脂注入路径。评估最初将集中在对缝合的夹芯板进行标准化的ASTM测试，并将结果与可比的未缝合的板材进行比较。将进行额外的专门测试，以评估卡夫拉缝合带来的损害容忍度的提高。终于来了。我们将探索基于有限元的分析方法，这些方法可用于为特定应用设计优化的缝合配置。如果我们在这项探索性研究中取得成功，我们将证明缝合的夹层结构在允许低成本加工的同时，提供了显著的损伤容限和层间强度。

An exploratory research program is planned to develop and assess through the thickness stitching of composite sandwich structures. We will explore the feasibility and potential benefits obtained by stitching foam core sandwich panels with Kevlar yarns. To offer low cost manufacturing, we propose to manufacture stitched sandwich panels using low-cost, out-of-autoclave processing. Sandwich panels will be stitched in a dry perform state, vacuum bagged, and infiltrated using Vacuum Assisted Resin Transfer Modeling (VARTM) processing. The through-the-thickness stitches will provide resin infusion paths to the facesheet adjacent to the tool surface. Evaluation will focus initially on performing standardized ASTM tests on the stitched sandwich panels and comparing results with comparable unstitched panels. Additional specialized tests will be performed to evaluate the increase in damage tolerance provided by the Kavlar stitched. Finally. We will explore finite element based analysis methodologies that may be used to design optimized stitching configurations for specific applications. If we are successful in this exploratory research, we will demonstrate that stitched sandwich structures offer a significant increase in damage tolerance and interlaminar strength while allowing for low cost processing.