SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Contents include the folowing: Virtual NASA Data Center (NDC) overview. NDC challenges. NDC present and future. NDC environment.NDC decomposition NDC opportunities. NDC solution: Horizontally and vertically scalable. Adaptable to new business/mission areas. Competitive-cost and quality. Superior service delivery.
An idea is put forth for a nondestructive characterization (NDC) generated algorithm-N curve to replace a S-N curve. A scenario for NDC life determination has been proposed. There are many challenges for the NDC life determination and prediction, but it could yield a grand payoff. The justification for NDC life determination and prediction is documented.
Damping measurements have been taken on ceramic matrix composite (CMC) turbopump blisks in the as fabricated, post proof testing, and post turbopump testing conditions. These results indicate that damping is able to quantify fatigue of the CMC blisk. This gives hope for the potential of determining the actual and residual life of CMC materials using a combination of nondestructive techniques. If successful, then this new paradigm for life prediction of CMCs could revolutionize the approach for designing and servicing CMC components, thereby significantly reducing costs for design, development, health monitoring, and maintenance of CMC components and systems. The Nondestructive Characterization (NDC) life prediction approach would complement life prediction using micromechanics and continuum finite element models. This paper reports on the initial concept of NDC life prediction and how changes in damping and ultrasonic elastic modulus data have established the concept as a possibility.
Recent results indicate that the specific damping capacity and resonant frequency measurements taken periodically during a component's lifetime is able to quantify the mechanical fatigue of CMCS. This gives hope for the potential of determining the actual and residual life of CMC materials using a combination of nondestructive techniques. If successful, then this new paradigm for life prediction of CMCs could revolutionize the approach for designing and servicing CMC components, thereby significantly reducing costs for design, development, health monitoring, and maintenance of CMC components and systems. The Nondestructive Characterization (NDC) life prediction approach would complement life prediction using micromechanics and continuum finite element models. This paper reports on the initial concept of NDC life prediction, a review of the C/SiC blisk damping data, and how changes in the specific damping capacity & ultrasonic elastic modulus data have established the concept as a possibility.
The purpose of this project is to utilize Ruby on Rails to create a web application that will replace a spreadsheet keeping track of training courses and tasks. The goal is to create a fast and easy to use web application that will allow users to track progress on training courses. This application will allow users to update and keep track of all of the training required of them. The training courses will be organized by group and by user, making readability easier. This will also allow group leads and administrators to get a sense of how everyone is progressing in training. Currently, updating and finding information from this spreadsheet is a long and tedious task. By upgrading to a web application, finding and updating information will be easier than ever as well as adding new training courses and tasks. Accessing this data will be much easier in that users just have to go to a website and log in with NDC credentials rather than request the relevant spreadsheet from the holder. In addition to Ruby on Rails, I will be using JavaScript, CSS, and jQuery to help add functionality and ease of use to my web application. This web application will include a number of features that will help update and track progress on training. For example, one feature will be to track progress of a whole group of users to be able to see how the group as a whole is progressing. Another feature will be to assign tasks to either a user or a group of users. All of these together will create a user friendly and functional web application.
The Popov criterion is applied to control system analysis and design. Nonlinear dynamic compensators (NDC) are introduced which ensure absolute stability without penalizing the available feedback.