NASA Langley Research Center
June 3 – August 16, 2019
Goals of your project/s:
During my internship, I was working on the Advanced Composites Project, which has the goal to reduce certification time of advanced composite structures by 30%. One aspect of this project is to develop a physics-based simulation tool for predicting defects (porosity and fiber waviness) during the cure process. My goal for the project was to utilize an in-situ composite cure monitoring and defect detection system recently developed at NASA LaRC to assist validation of the simulation tool. This consisted of running multiple (~8) experiments during cure in order to verify that the developed system was able to not only detect the defects of the composite but also monitor how they evolve. The two main approaches consisted of completing experiments with intentionally embedded defects and then later transitioning to fabricating laminates with processing induced porosity. Verifying the detection system in an oven aids the transition from oven to autoclave.
Describe what you did during the internship.
The ten weeks I spent at Langley Research Center was a great learning experience. I was able to help in the verification of an in-situ cure monitoring and defect detection system for composites, which is what I spent the majority of my time doing. The initial approach to verify the system was to determine if it would detect intentionally placed defects embedded into the laminate during a cure cycle. Multiple composite laminates were laid up by hand with areas of glass microspheres embedded between layers to simulate porosity. The laminates were then cured in an industrial oven while a temperature insulated ultrasonic scanning system would monitor the laminate as it cured. Running a cure cycle ranged from five to ten hours depending on the material chosen and had to be closely monitored to collect data from the ultrasonic scanner. The day after an experiment would consist of processing and analyzing the data to determine the success of the experiment and the behavior of the composite. Based on the results, another experiment would be prepared to either validate the previous experiment or make changes. The material choice, defect type, location, and intensity were all varied in multiple experiments in order to validate the system.
Did you achieve your goals? What were the results and conclusions?
The goal of my internship was achieved. The system was able to detect both the location and intensity of the embedded defects as well as processing induced porosity throughout the cure cycle. With the success of the experiments, there was now more confidence in transitioning the system from an oven to an autoclave. Another added benefit was the data collected is going to be utilized to help validate the physics model.
Describe positive lessons learned from this experience:
A positive from my internship was being able to learn the value of having a good mentor in the workplace. My mentor did an amazing job not only helping me be a better intern but also helped me grow professionally. Having someone to help show me the ropes of the position made for a smooth transition. I also learned to appreciate the environment I was in, the department I worked in was very welcoming and it felt like a place for growth.
Describe negative lessons learned from this experience:
The importance of communication in order for a project to proceed. I learned very quickly that because I was the primary person running these experiments, I needed to be able to document what I did very well for future testing and publication of results. Early on in the internship, there was a situation when I did not label a few laminates from previous experiments that my mentor wanted to investigate. If I were not there to know which laminate corresponded to which experiment, then there would not have been a way to look at a specific experiment’s laminate.