Studying the heterogeneity of discontinuous fiber composites using a new full-field strain measurement system

Johanson, K.; Harper, L. T.; Johnson, M.; Kennedy, A.; Warrior, N. A.

Abstract

In this paper a new multi camera digital image correlation (DIC) system is used to view strain fields from opposing surfaces of discontinuous carbon fiber composites loaded in tension. The system is investigated to understand if DIC can be used to correlate the cause of damage initiation to the underlying fiber architecture within heterogeneous composites. Results indicate that whilst potential final failure sites can be detected at low global strains in the form of strain concentrations, they are not always evident on both sides of the sample. Localized variations in the strain fields exist at the meso (tow) scale in materials with stochastic architectures. Studying the development of strains on both sides of the sample at even modest global strains gives an early indication of where damage is likely to initiate, which can then be related back to underlying architectural features identified by ultrasonic C scan. However, pin-pointing the specific region of ultimate failure is not possible using these techniques alone. This phenomenon is dependent on the specimen thickness and the fiber volume fraction, which explains why ordinarily it can be difficult to associate the location of fracture sites with features observed in conventional single-sided DIC strain profiles.

Citation

Johanson, K., Harper, L. T., Johnson, M., Kennedy, A., & Warrior, N. A. (2013, July). Studying the heterogeneity of discontinuous fiber composites using a new full-field strain measurement system. Paper presented at ICCM International Conferences on Composite Materials, Montréal, Canada

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: ICCM International Conferences on Composite Materials
• Start Date: Jul 28, 2013
• End Date: Aug 2, 2013
• Deposit Date: Mar 19, 2024
• Public URL: https://nottingham-repository.worktribe.com/output/13754234
• Publisher URL: https://www.iccm-central.org/Proceedings/ICCM19proceedings/papers/JOH80471.pdf