CompositesWorld
Issue link: https://cw.epubxp.com/i/546021
AUGUST 2015 48 CompositesWorld FEATURE / STRUCTURAL HEALTH extensively and inspected with manual NDT (e.g., conventional ultrasound) inside vs. outside to verify the system's damage detec- tion and assessment performance. Advancing CBM to save weight Te next step beyond CBM (Generation 2 in Fig. 1, p. 45) is to use data collected from these applications to enable a less conser- vative, lighter weight design for structures in future aircraft. Bockenheimer cites Airbus' Vertical Tail Plane Next Generation (VTP-NG) rib de-bonding detection system as an example. Te VTP-NG program, which has been advanced by the Composite Technology Center (CTC, Stade, Germany), proposes a novel design and manufacturing approach for the vertical tail, based on composite ribs bonded onto cored sandwich skins. However, to determine if rib debonding has occurred in service via conventional NDT, the structure must be opened to access the interior. "Tis makes the structure too difcult to inspect, so a bonded solution would be difcult to realize," explains Bockenheimer. "We proposed using CVM to detect rib debonding at any time we want, without having to access the inside. So now, we can work out the design for improved weight and decreased production costs." Although it ofers much promise, the VTP-NG program is still in development. Straightening the path to qualifcation But what is actually required for such promising SHM applications to reach commercial service, and how long will it take? "Until now, the path for qualifcation and certifcation has not been very well defned or straight," observes TESTIA's Speckmann, "and SHM technology companies have spent a lot of money and time." He adds that the framework being developed for Airbus' SHM V&V; Center emerged out of its A350 SHM door-surround program, with the goal to provide SHM technology companies with a clear way to get onto commercial aircraft without going bankrupt. "It's not in Airbus' interest for these compa- nies to waste time and money," says Speckmann. It is planned that the V&V; Center will become part of the Center for Eco-ef- cient Materials & Technologies (ECOMAT, Bremen, Germany), a locally funded science and industry research collaborative focused on new technologies in lightweight, multifunctional construction for not only aerospace but also automotive, wind energy, marine and building and construction applications. Bockenheimer explains that Airbus MP&T; is responsible for the development and qualifcation of SHM technologies. "We have formed multidisciplinary teams to integrate the structural sensing technology with the aircraft monitoring system architecture." Tis approach also has led Airbus to establish a comprehen- sive set of key requirements based on the type of SHM detection. The ultimate benefts of SHM are anticipated when sensors can be incorporated during manufacture .... FIG. 3: Sensor integration Both CVM and SMART Layer sensors (above) were developed to be built into composite structures rather than applied as a retroft. This illustrates the fnal step in SHM development: Integration of sensors during part manufacture to provide quality control through assembly as well as CBM and lightweight design benefts for complete lifecycle monitoring (see diagram at left). Source (above) | Acellent Technologies Source (left) | Airbus