This paper reports a study concerning the penetration of eddy current density in the material when sub-surface linear cracks exist. Simulations were performed for a set of different lengths and depths of the crack using a sinusoidal excitation current with uniform magnetic field distribution. The dependences between the length/depth of the crack and the magnetic field components ( B x and B z ) were analyzed.
This research work relates to the soldering process observation in reflow ovens. The need for full continuous monitoring of reflow processes is more and more in the electronics technology. Today process monitoring of reflow soldering is based on temperature curve as a minimum requirement. A real time video observation functionality which allows control the flow of product through the reflow oven, this feature can make a very powerful control system. Based on this need for full process control, it has been developed a prototype system for visual monitoring of soldering process in an inline...
In this paper, an on-component triaxial capacitive probe for clearance measurement (static and dynamic measurement of distance) is proposed and studied. The device is designed to be deposited onto machinery components or complex structures and is aimed at reducing the impact of probe mounting on the monitored component. The problem is discussed from a theoretical point a view and then supported by the development of a prototype in screen printed technology. The results prove the feasibility of this innovative device.
There has been an increasing trend in using ceramics in the application areas where high hardness and thermal resistance are necessary, especially in energy production branch where gas turbines are coated with ceramics. The paper introduces experiments and results of ceramics machining using regular cutting tool geometry. Two machining strategies were analysed (wave form and cycloid), the number of critical process parameters were reduced significantly and remarkable tool life extension was reached using the test machine build by the authors.
This paper presents the results of numerical simulation, used for the welding technology development of a 13 m long chassis made of high strength steel. Finite element modeling aimed to describe the welding distortions, and the deformations resulted by using flame straightening of the much critical edges of the product. In FEM work SimuFact and MARC software were used. Physical simulation was also applied in order to validate the FEM results. Simulations focused mainly to the effect of the welding direction along the free displacement edges.
The Functional Safety is the part of overall safety of a system, called Safety Instrumented System that depends on the system operating correctly in response to its inputs. The paper focuses on safety loop assessment using the standard IEC 61508 and presents a case study concerning the evaluation of the Probability of Failure on demand (PFD) for a complex Safety Instrumented System including redundancy in modern application.
The paper presents the detailed analysis of the Radial Basis Function (RBF) neural network application for diagnostics of analog systems. In most cases RBF networks are used in the approximation tasks. In this work the network is used as the fault classifier. Because RBF networks are known to be dependent on the size of training data, the procedure to minimize the amount of the learning examples was proposed. The classifier is tested on the model of the electronic filter, which, was also diagnosed by alternative methods, such as Multilayered Perceptron and Support Vector Machine....
In this paper, a statistical algorithm for the assessment of Photovoltaic (PV) modules reliability is presented. The algorithm is based on the application of Monte Carlo simulations for the propagation over time of the stochasticity of the various failure modes occurrence time and their effect on the output power degradation.
In this paper we describe a proposal of distributed power control system and a demand estimation model for suppressing total power usage. The main components of the system are smart power outlets (SPOs) which can suppress the total power usage under the contract or saving target power and also can avoid excess circuit current to prevent a breaker trip by using mutual communication. The method to suppress the total power is by stochastic way incorporating standby rate, which is calculated by using an estimation model of total power demand. We implemented SPOs with defining communication...