NASA Langley Research Center

Keywords: Composites, Adhesives, Process Monitoring, MATLAB, Ultrasonics

Background

Composite structures are seeing increasing usage in modern aircraft due to their high strength-to-weight ratio when compared to traditional components such as aluminum. Single-aisle commercial aircraft like the Boeing 737 rely on hundreds of thousands of fasteners to join composite structural components. In order to meet safety standards, fasteners are preferred over adhesives due to their reliability, despite decreasing the structural performance of composites. However, the sheer number of fasteners also increases the aircraft's weight, manufacturing time, repair time, and ultimately cost. At NASA Langley Research Center, I worked on the Transformational Tools and Technology (TTT) Project under the Advanced Materials and Processing Branch (AMPB). The goal of this project at is to assist in the development of an advanced certification model for adhesively bonded composite structural components in order to more effectively levy the benefits of composite structures over metal structures in future aircraft. I investigated the dependence of adhesive bondline thickness of various parameters including cure cycle, autoclave + vacuum bag cure, vacuum bag only, oven cure (simulates bag leak), and number of adhesive plies..

What I Did

• Fabricated, bonded, cured, and analyzed composite panels.

• Operated an out-of-autoclave ultrasonic immersion scanner and an in-situ autoclave scanner to characterize properties of the adhesive bondline including thickness and void content, pre-, during-, and post-cure.

• Developed multiple MATLAB tools to analyze ultrasonic scanning data.

• Characterized adhesive block to determine velocity in order to convert time-of-flight to thickness.

• Worked with suppliers to acquire quotes for various project materials.

Skills Used

• MATLAB

• ImageJ

• Composite Processing

• Adhesives

• Ultrasonic Scanning