Automatic Fiber Placement ( AFP ) Technology , Actual State and Future Improvement through Using NDT ( Ultrasonic ) Equipment in On-line Processing Prof . PhD
In this paper are presented all of the technologies used for research at the Institute for Advanced Composites and Robotics (IACR). Focus is put on the automated fiber placement (AFP) technology and the equipment used to perform this technology. Analysis presented, refer to possible mistakes in the final product, composite part intended to be a primary structure of an airplane, due to the inability to know the influence of the compacting roller, or the characteristics of the prepreg on the occurrence of micro voids in the laminate of the part produced. As a response to this acknowledgement, preliminary research is done at IACR where ultrasonic sensor is used for nondestructive testing (NDT) in composite materials. This preliminary research has shown that it should be further inspected whether ultrasonic sensor following the compacting roller, could improve the impacting process and diminish the number of voids in the final product.
Development of a theoretical model for a solvent-type prepreg manufacturing process
Abstract This paper presents a theoretical study of the impregnation of continuous fiber or cloth with thermosetting resin matrix materials. A model is developed to describe the resin, the volatile content and the coated resin thickness as functions of impregnation velocity for a solvent-type, vertical impregnating process. A power law is employed to account for the effect of shear rate on the resin velocity in the model. Results are obtained methodically through the separation of variables. A dimensionless number, called the impregnation number, is derived which expresses the relative importance among the viscous, inertial and gravity forces in the impregnation process. It is found that the dimensionless number is important in characterizing the maximum possible resin content for a given condition, and that an increase in the resin viscosity is much more effective than an increase in the impregnation velocity in achieving higher resin content. The volatile content is controlled by a combination of the impregnation velocity and the oven length. The predicted volatile contents agree well with the experimental results for a 177°C prepreg. The model is valid for predicting volatile content in the practical impregnation process.
Arc flash hazard assessment in the mining industry
When it comes to electrical safety in the workplace, arc flash has become the most prominent topic over the past decade. The Occupational Safety and Health Administration (OSHA, including state chapters) is the only government body that recognizes NFPA-70E, Standard for Electrical Safety in the Workplace. However, OSHA does not have jurisdiction in mining operations. Electrical safety for the metal and nonmetal surface mining industry is covered by the Code of Federal Regulations (CFR) Title 30, Part 56, Subpart K (Electricity). The Mine Safety and Health Administration (MSHA) is responsible for enforcing electrical safety in mining operations. CFR Title 30 does not reference personal protective equipment (PPE) to protect electrical workers against arc flash hazards. This paper provides maintenance and safety personnel in surface Metal/Nonmetal mining operations with a step by step guide to implementing an electrical safety program that meets the requirements of MSHA, CFR Title 30 and NFPA-70E.