title: Embedding piezoresistive pressure sensors to obtain online pressure profiles inside fiber composite laminates.
abstract: The production of large and complex parts using fiber composite materials is costly due to the frequent formation of voids, porosity and waste products. By embedding different types of sensors and monitoring the process in real time, the amount of wastage can be significantly reduced. This work focuses on developing a knowledge-based method to improve and ensure complete impregnation of the fibers before initiation of the resin cure. Piezoresistive and capacitive pressure sensors were embedded in fiber composite laminates to measure the real-time the pressure values inside the laminate. A change of pressure indicates resin infusion. The sensors were placed in the laminate and the resin was infused by vacuum. The embedded piezoresistive pressure sensors were able to track the vacuum pressure in the fiber composite laminate setup, as well as the arrival of the resin at the sensor. The pressure increase due to closing the resin inlet was also measured. In contrast, the capacitive type of sensor was found to be inappropriate for measuring these quantities. The following study demonstrates real-time monitoring of pressure changes inside the fiber composite laminate, which validate the use of Darcy's law in porous media to control the resin flow during infusion.
authors.affiliation: Institute for Microsensors, Actuators and Systems (IMSAS), University of Bremen, Otto-Hahn-Allee, NW1, 28359 Bremen, Germany. mkahali@imsas.uni-bremen.de.
authors.forename: Maryam Kahali
authors.initials: MK
authors.lastname: Moghaddam
authors.affiliation: Faserinstitut Bremen e.V. (FIBRE), Gebäude IW3, Am Biologischen Garten 2, 28359 Bremen, Germany. breede@faserinstitut.de.
authors.forename: Arne
authors.initials: A
authors.lastname: Breede
authors.affiliation: Faserinstitut Bremen e.V. (FIBRE), Gebäude IW3, Am Biologischen Garten 2, 28359 Bremen, Germany. brauner@faserinstitut.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Brauner
authors.affiliation: Institute for Microsensors, Actuators and Systems (IMSAS), University of Bremen, Otto-Hahn-Allee, NW1, 28359 Bremen, Germany. wlang@imsas.uni-bremen.de.
authors.forename: Walter
authors.initials: W
authors.lastname: Lang
references.citation: Rev Sci Instrum. 2007 Jan;78(1):015110
references.pmid: 17503949