Damage detection of carbon fibers in filament winding machines using an electrical resistance method

The aim of this research project is to detect the presence of fiber damage which occurs during the pretensioning of carbon fibers during the Filament Winding (FW) manufacturing process. The property of electrical conductivity of the carbon fibers was investigated to determine the existence and level of fiber damage. An experimental system was designed and developed to simulate the pretension system of a FW machine and measure the electrical change of broken fibers during the winding process. Toray T1000G-12K type of carbon fiber was used in the experimental stage of this research project. The damaged fibers were later used to obtain tension test pieces to evaluate the amount of damage which was caused by the pretensioning unit. The tension test was carried out according to ASTM 4018-99. The results demonstrated that the electrical conductive property of carbon fibers can be effectively used to evaluate the damage which occurs during the pretensioning in the FW process

Influence of pretension on mechanical properties of carbon fiber in the filament winding process

The present study has investigated the effect of the roving tension (pretension force) on the strength of continuous carbon fiber used in the Filament Winding (FW) process. Pretension force is generally applied to composite products manufactured by FW technology to lay out the carbon fiber onto the cylindrical tube in a correct way. However, a considerable amount of damage occurs in the fibers during fiber movement trough pulleys in the pretension unit. A winding system was designed to simulate the process to understand the effects of the parameters such as roving tension, pulley diameter, and contact angle between pulley and fiber. Several experimental tests have been performed by changing pulley diameters and tension forces to understand the effect of these parameters. According to these experiments, the angle between the pulley and the amount of force applied to the carbon fiber generate the damage on the carbon fiber. Tension tests were also conducted to evaluate the strength of the damaged and undamaged carbon fiber. Experimental results indicate that the tensile strength of carbon fiber is reduced by 10 to 43% because of a change to the roving tension (pretensioning) parameters

Characterization of electrothermal micro-actuator using image processing algorithm

WOS:0006267225000403D fabrication technology has gained a lot of attention recently, with the rapid fabrication of 3D parts for use in various applications. This article presents an electrothermal micro-actuator's characterization study fabricated using digital light processing (DLP), one of the 3D manufacturing methods. This actuator has been designed and fabricated to move in two directions according to the specified criteria. Three different experiments were conducted during the fabrication process. During the fabrication process of the first two experiments, deterioration or breakage occurred in the micro-actuator structure. These problems did not occur in the fabrication of the 3rd experiment. A characterization test setup was created to observe the displacement of the actuator under different operating voltage values. This setup includes an optical microscope and digital camera to observe displacements at the probe station. An image processing algorithm was used to detect the observed displacements. In experimental studies, the operating voltage was increased from 0V to 1V until deterioration or breakage in the micro-actuator structure was observed. When 6V voltage is applied to the micro-actuator, a maximum displacement of 3.84 mu m occurred in each direction. When more than 6V voltage is applied to the micro-actuator, deformations or breaks occurred in the actuator arms. As a result, the micro-actuator's design is bi-directional, so its maximum displacement is 7.68 mu m

Caliper simulation using computer for vocational and technical education

In this study a caliper simulation was developed as computer application for using in the Vocational Education and Training (VET) and Distance-based training. This simulation was developed for teaching the caliper as measurement tool based Metric and Whitworth measurement systems. The developed caliper simulation introduced in detail step by step as user guide. The vernier scales are simulated as 1/10, 1/20 and 1/50 for metric measurement system and 1/64, 1/128 and 1/1000 for Whitworth measurement system. This simulation can easily be download and setup as computer software. To the best of the authors’ knowledge, this is the most important application for students to study everywhere they would like

Fabrication and Experimental Study of Micro-gripper with Electrothermal Actuation by Stereolithography Method

The aim of the study is to get high displacement values with low actuation voltage from the micro-gripper fabricated by stereolithography (SLA) method. Micro-grippers are devices based on a micro-electro-mechanical system (MEMS) preferred for manipulation and assembly in micro-fabrication. This article presents the modeling, fabrication, and experimental studies of a U-type electrothermal MEMS micro-gripper. The fabrication of the gripper was made by SLA, which is one of the additive manufacturing methods. The arm tip displacement of the gripper has been characterized in real-time by optical microscopy. In electrical characterization studies, the electrical voltage was applied to the pads of the micro-gripper. This voltage value was increased starting from 0V with 1V increments until deterioration was observed in the gripper. The micro-gripper is shown to actuate to a maximum opening displacement of 28.35 mu m at an applied voltage of 5V. The models are employed to examine key factors of the micro-gripper's performance including temperature distribution, displacement, and stresses based on an elastic analysis of structures. Experimental results for the displacement of the micro-gripper's arm tips were found to be in good agreement with the simulation results

Caliper simulation using computer for vocational and technical education

In this study a caliper simulation was developed as computer application for using in the Vocational Education and Training (VET) and Distance-based training. This simulation was developed for teaching the caliper as measurement tool based Metric and Whitworth measurement systems. The developed caliper simulation introduced in detail step by step as user guide. The vernier scales are simulated as 1/10, 1/20 and 1/50 for metric measurement system and 1/64, 1/128 and 1/1000 for Whitworth measurement system. This simulation can easily be download and setup as computer software. To the best of the authors’ knowledge, this is the most important application for students to study everywhere they would like

Ultimate strength of quasi-isotropic laminates in tension: theoretical and experimental analysis

International audienceno abstrac

Ultimate strength of quasi-isotropic laminates in tension: theoretical and experimental analysis

International audienceno abstrac