Industrial Applications Thanks Research Articles

Multipath QoS-driven routing protocol for industrial wireless networks

The Industry 4.0 concept targets the interconnection and computerization of traditional industries to improve their adaptability and utilize efficiently their resources. Industrial wireless networks will play a key role within the Industry 4.0 as they will facilitate the deployment of novel industrial applications thanks to the flexible and reconfigurable wireless connection of industrial devices. Significant advances are still necessary to enable the deployment of reliable industrial wireless networks capable to guarantee the strict QoS (Quality of Service) requirements of industrial applications in harsh propagation conditions. This paper contributes towards this objective with a novel multipath routing protocol that identifies and establishes the necessary redundant routes between any pair of nodes of a wireless network in order to satisfy the reliability and delay QoS levels demanded by industrial applications. The proposed protocol is here presented and analyzed under the framework of the WirelessHART standard given its important industrial adoption. However, it can also be adapted to other centralized TDMA-based multi-hop wireless networks.

Elastoplastic buckling and post-buckling analysis of sandwich columns

Sandwich structures are widely used in many industrial applications thanks to their interesting compromise between lightweight and high mechanical properties. This compromise is realized thanks to the presence of different parts in the composite material, namely the skins which are particularly thin and stiff relative to the homogeneous core material and possibly core reinforcements. Owing to these geometric and material features, sandwich structures are subject to global but also local buckling phenomena which are mainly responsible for their collapse. The buckling analysis of sandwich materials is therefore an important issue for their mechanical design. In this respect, this paper is devoted to the theoretical study of the local/global buckling and post-buckling behavior of sandwich columns under axial compression. Only symmetric sandwich materials are considered with homogeneous and isotropic core/skin layers. First, the buckling problem is analytically addressed, by solving the so-called bifurcation equation in a 3D framework. The bifurcation analysis is performed using an hybrid model (the two faces are represented by Euler–Bernoulli beams, whereas the core material is considered as a 2D continuous solid), considering both an elastic and elastoplastic core material. Closed-form expressions are derived for the critical loadings and the associated bifurcation modes. Then, the post-buckling response is numerically investigated using a 2D finite element bespoke program, including finite plasticity, arc-length methods and branch-switching procedures. The numerical computations enable us to validate the previous analytical solutions and describe several kinds of post-critical responses up to advanced states, depending on geometric and material parameters. In most cases, secondary bifurcations occur during the post-critical stage. These secondary modes are mainly due to the modal interaction phenomenon and give rise to unstable post-buckled solutions which lead to final collapse.

Delay-Aware Medium Access Schemes for WSN-Based Partial Discharge Measurement

Wireless sensor networks (WSNs) are widely preferred measurement and monitoring tools for a large variety of industrial and environmental applications thanks to their low-cost, energy-efficiency, flexibility, and ease of deployment. However, the use of WSNs for measuring and monitoring industrial applications generating data at high rates, such as online monitoring of partial discharge activities in high voltage equipment in the power grid, presents a significant challenge for the system operators. In such applications, packet arrival rates could increase rapidly due to the occurrence of cascaded faults in the monitored environment. The WSNs with multihop topologies could experience excessive delays and an increase in packet drop of vital data due to the overwhelming increase in the packet arrival rates. Therefore, there should be an optimum operating point of the network where high packet arrival rates and low latency can be maintained at the same time. Thus, there is an immediate need for carefully designed quality of service (QoS) differentiation schemes that can guarantee the delivery of critical data with minimum latency and least loss. In this paper, we present a QoS differentiation scheme for high priority data in multihop WSNs based on an optimization scheme. Analytical and simulation results show that our proposed scheme significantly reduces the delay while maintaining high data delivery ratios and energy efficiency of the network.

Microstructure Evolution of Al-Mn-Si-Fe Alloy Studied by In-situ Transmission Electron Microscopy

Equal channel angular pressing is one of the techniques of severe plastic deformation, which produce materials with sub-micrometric grains. Materials with grains under 1 m are of great importance for industrial applications thanks to enhanced strength at lower temperatures and formability at elevated temperatures. One of the possible ways how to enhance microstructure stability of aluminium alloys at elevates temperatures is addition of small amount of zirconium. In our study, heat treatment at 450 °C leads to precipitation of Al3Zr phase. After ECAP these particles postpone recrystallization above 400 °C. However, in the material without Al3Zr particles the recrystallization resistance is comparable thanks to impact of -Al(Mn,Fe)Si phases. More over, initial microhardness after ECAP is higher for the alloy, which was not heat-treated at 450 °C before ECAP, thanks to higher dislocation density and solid solution strengthening by Mn atoms.

CFD comparison with centrifugal compressor measurements on a wide operating range

Centrifugal compressors are widely used in industrial applications thanks to their high efficiency. They are able to provide a wide operating range before reaching the flow barrier or surge limits. Performances and range are described by compressor maps obtained experimentally. After a description of performance test rig, this article compares measured centrifugal compressor performances with computational fluid dynamics results. These computations are performed at steady conditions with R134a refrigerant as fluid. Navier-Stokes equations, coupled with k-e turbulence model, are solved by the commercial software ANSYS-CFX by means of volume finite method. Input conditions are varied in order to calculate several speed lines. Theoretical isentropic efficiency and theoretical surge line are finally compared to experimental data.

An Application of the Modified PID Control System for Heat Flow Experiment

The Proportional-Integral-Derivative (PID) controller structure is the most widely used in industrial applications thanks to its structural simplicity and applicability in solving practical control problems. It is not, however, almighty. Yamada and Hagiwara proposed design modified PID controllers to make control for any plant stable and make admissible sets of P, I, and D parameters mutually independent. Applying modified PID control to practical plants requires that the influence of disturbance in the plant be considered. In many cases, this disturbance is unknown, making it difficulty to attenuate. Although designs have been proposed for modified PID control to attenuate unknown disturbances, little has been done in examining the attenuation of unknown disturbances. We demonstrate the effectiveness of modified PID control in attenuating unknown disturbances for temperature control in heat flow experiments.

Science, technology and innovation

Induction motors are important part of safe and efficient running of any industrial plant. These motors are often used in industrial applications thanks to their usability and their robustness. Faults and failures of induction machine can lead to excessive downtimes processes; generate large losses in revenues and long term maintenance. Early detection of motor abnormalities would help avoiding costly breakdowns. In this paper a diagnostic technique of induction motor broken rotor bars is presented. The applied method is the so-called Motor Current Signature Analysis (MCSA) which utilized the results of spectral analysis of the stator current. The broken rotor bars and rings will cause twice slip frequency side bands around the supplying frequency. The fault detection method consists in monitoring of stator phase current spectrum. Twice slip frequency side bands around the main frequency detected by spectral analysis is an indicator of the broken bars. The experimental results show the efficiency of the method.