| About this Abstract |
| Meeting |
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
| Symposium
|
2024 ASC Technical Conference, US-Japan Joint Symposium, D30 Meeting
|
| Presentation Title |
Development of a Higher-Level Building Block Testing Standard Using Seven Point Bend Configuration for Performance Evaluation at Scale |
| Author(s) |
Christopher Boshers, Mohamed Shafie, Waruna Seneviratne, Harishanker Nadason, John Tomblin |
| On-Site Speaker (Planned) |
Christopher Boshers |
| Abstract Scope |
Certification of composite air vehicles is accomplished through extensive test campaigns to demonstrate that the structure meets all strength, durability, damage tolerance, and environmental resistance requirements. While the processes for defining the building block test campaign are well defined and specify the use of various adjustment factors (environmental, statistical, and load enhancement factors), they are based on the coupon-level. These adjustment factors thus can be overly conservative, ignoring the benefits of scaling-effects observed for most failure modes.
In this work, a standard seven-point bend element test configuration representative of a common aerospace structural component is proposed for inclusion in future building block certification efforts. This configuration enables a more efficient means of assessing the effects of manufacturing and in-service nonconformances. The test article is large enough to capture scaling effects of many common failure modes and defects, while also being small enough to fit into environmental chambers during tests, enabling environmental compensation factors determination at the element level. With the test configuration exerting out-of-plane loads mimicking actual complex structural loads, damage at the skin/stiffener interface undergo mixed-mode crack propagation. In this initial assessment, a secondary bonded skin/stringer construction was investigated to determine impact of surface preparation techniques. Mechanical abrasion was compared to an atmospheric plasma treatment (APT) process at room temperature and elevated temperature, saturated environmental conditions. The results of these tests support the adoption of this test process as a standard for use in building block testing to reduce the degree of conservatism in future composite vehicle design. |
| Proceedings Inclusion? |
Definite: Post-meeting proceedings |