Design and Evaluation of a Reinforced Advanced-Grid Stiffened Composite Structure
Abstract : A composite grid-stiffened structure concept was selected for the payload fairing of the Minotaur launch vehicle. Compared to previous designs, this concept is lighter weight and requires reduced manufacturing costs. Various failure mechanisms were examined for the composite grid-stiffened structure. The controlling criterion for this design was determined to be joint peel-off failure. The identification of this failure mechanism and the assessment of bounding strains to control it, required extensive test and analysis effort. The final fairing design incorporated an undesirably thick skin to reduce the strain between the skin and ribs. This project investigated a means of controlling joint failure of the un-reinforced grid-stiffened structure in an effort to reduce the skin thickness. Implementing lightweight foam inserts between the stiffeners on the interior of the fairing delayed failure to higher loads. A foam reinforced test panel, designed with equal mass to the current structure, withstood a substantially greater compressive force. The alternative concept also demonstrated an improved response, failing in global buckling instead of experiencing early failure due to joint strain.
Thermal Buckling Analysis and Optimization of Curvilinearly Stiffened Plates with Variable Angle Tow Laminates
This paper presents results from thermal buckling analysis and optimization of stiffened composite panels with variable angle tow (VAT) laminates and curvilinear stiffeners. Considering the meshing...
Chapter 1 – Nanotechnology: A Toolkit for Cell Behavior
Tissue engineering seeks to effectively manipulate cellular populations to improve the function of damaged or diseased tissues and organs. Many techniques can affect cell behavior; however, in order to maintain desirable function, scientists and engineers design solutions that are as biomimetic as possible. True biomimeticity is very challenging without the incorporation of nanotechnology. Since cells in human tissues are surrounded by a 3D hierarchical tissue extracellular matrix containing numerous nano components, a revolutionary change in tissue engineering is to explore biomimetic nanobiomaterials and advanced 3D nano/microfabrication techniques for creating novel tissue constructs and regulating cell behavior. This chapter will provide an overview of recent nanotechnology in tissue engineering applications. We will put special emphasis on integrating cutting-edge 3D nano/microfabrication techniques with nanobiomaterials for complex tissue and organ regeneration.