A self referenced fiber optic refractive index sensor is developed to measure quantitative cure extent of epoxy. In case the sensor is applied to in situ cure monitoring of epoxy composites, each sensor embedded in...A self referenced fiber optic refractive index sensor is developed to measure quantitative cure extent of epoxy. In case the sensor is applied to in situ cure monitoring of epoxy composites, each sensor embedded in different location within the structure is self referenced and can be normalized to a common scale. Therefore, the real time comparative of each sensor’s output becomes possible and variations in the extent of cure at different locations can be monitored. The developed sensor was used to monitor the isothermal cure of an epoxy system. The output of the sensor was compared with the results of the differential scanning calorimetry (DSC). The self referencing function of the sensor is confirmed.展开更多
With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely an...With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely and efficiently.In this paper, experiment results of viscosity measurement in composite cure process in autoclave using fiber optic sensors are presented. Based on the sensed information, a computer program is utilized to control the cure process. With this technology, the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.展开更多
For more than 7 years,our research work is focussed upon the electrical behavior of carbon fiber reinforced composites.Effectively carbon/polymeric matrix laminates can be considered as an electri-cally conductive net...For more than 7 years,our research work is focussed upon the electrical behavior of carbon fiber reinforced composites.Effectively carbon/polymeric matrix laminates can be considered as an electri-cally conductive network(i.e.carbon fibers)embedded in an insulat-ing medium(i.e.the polymeric matrix).Consequently,from an electrical point of view laminated composites have been modelled owing to combinations of electrical resistances(i.e.fibers themselves and the contact points between the fibers)and capacitances(i.e.polymeric matrix).During their manufacturing,composite material such as thermoset matrix composites for instance,undergo various changes in their physical(including electrical and mechanical)prop-erties and in their geometrical characteristics.In fact,in the case of manufacturing processes such as oven curing(vacuum bag),auto-clave curing or heating plate press,beside the chemo-rheologi-cal changes,the laminated parts are the place of a compaction phenomenon inducing changes in fiber volume fraction and thick-nesses.The idea developed in this paper is that since the carbon/polymeric matrix laminate can be considered as an electrical network,it can then be view and used as a sensor for following the material state during the manufacturing process enabling thus defects to be detected and this without any additional sensing material or device.展开更多
文摘A self referenced fiber optic refractive index sensor is developed to measure quantitative cure extent of epoxy. In case the sensor is applied to in situ cure monitoring of epoxy composites, each sensor embedded in different location within the structure is self referenced and can be normalized to a common scale. Therefore, the real time comparative of each sensor’s output becomes possible and variations in the extent of cure at different locations can be monitored. The developed sensor was used to monitor the isothermal cure of an epoxy system. The output of the sensor was compared with the results of the differential scanning calorimetry (DSC). The self referencing function of the sensor is confirmed.
文摘With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely and efficiently.In this paper, experiment results of viscosity measurement in composite cure process in autoclave using fiber optic sensors are presented. Based on the sensed information, a computer program is utilized to control the cure process. With this technology, the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.
文摘For more than 7 years,our research work is focussed upon the electrical behavior of carbon fiber reinforced composites.Effectively carbon/polymeric matrix laminates can be considered as an electri-cally conductive network(i.e.carbon fibers)embedded in an insulat-ing medium(i.e.the polymeric matrix).Consequently,from an electrical point of view laminated composites have been modelled owing to combinations of electrical resistances(i.e.fibers themselves and the contact points between the fibers)and capacitances(i.e.polymeric matrix).During their manufacturing,composite material such as thermoset matrix composites for instance,undergo various changes in their physical(including electrical and mechanical)prop-erties and in their geometrical characteristics.In fact,in the case of manufacturing processes such as oven curing(vacuum bag),auto-clave curing or heating plate press,beside the chemo-rheologi-cal changes,the laminated parts are the place of a compaction phenomenon inducing changes in fiber volume fraction and thick-nesses.The idea developed in this paper is that since the carbon/polymeric matrix laminate can be considered as an electrical network,it can then be view and used as a sensor for following the material state during the manufacturing process enabling thus defects to be detected and this without any additional sensing material or device.
