Analysis of crane track degradation due to operation

This study presents a steel container crane movement analysis and assessment based on structural health monitoring (SHM). The accelerometers are used to monitor the dynamic crane behavior and a 3-D finite element model (FEM) was designed to express the static displacement of the crane under the different load cases. The multi-input single-output nonlinear autoregressive neural network with external input (NNARX) model is used to identify the crane dynamic displacements. The FEM analysis and the identification model are used to investigate the safety and the vibration state of the crane in both time and frequency domains. Moreover, the SHM system is used based on the FEM analysis to assess the crane behavior. The analysis results indicate that: (1) the mean relative dynamic displacement can reveal the relative static movement of structures under environmental load; (2) the environmental load conditions clearly affect the crane deformations in different load cases; (3) the crane deformations are shown within the safe limits under different loads.

Movement identification model of port container crane based on structural health monitoring system

RF chip CC2420 is a RF transceiver which conforms with ZigBee specification.According with the functions and operatioal principles of CC2420,it proposes a feasible low-power circuit design of ZigBee networks nodes which applies a PIC18F4620 processor and CC2420 RF transceiver.It also presents the application circuit of CC2420 and principle chart of power amplification.Testing shows that the transmission distance of two adjoining node can achieve 500 meters when RF emission power adjusts to 18dBm.

Design of ZigBee wireless networks nodes based on CC2420

Sensor nodes need much power;it is complicated to place their cables and signal can easily be interfered.So it is difficult to design power,communication and the circuit of high precision sampling in application of structure health monitoring.A high precision wireless strain sensor node was designed with combination the idea of intelligent sensor design with the advantages of wireless communication and solar energy.The design focused on power,amplifier,filter and wireless communication.The designed node showed a favorable effect and provided a high performance hardware platform for in-depth study on wireless strain sensor.The system run in high accuracy and practicality,low cost and power consumption,which means its promising application in structure health control.

Design and Implementation of a High Precision Wireless Strain Sensor Node


 Fracture of the metal structure is one of the foremost causes of accidents for portal cranes, and such an accident can be catastrophic, resulting in great loss of life and large expenses. Assessing the structural health of portal crane is important as it can keep security threats from further development. In an effort to evaluate the structural health of portal cranes in real time, an improved technique for order preference by similarity to an ideal solution (TOPSIS) model is presented in this paper. By integrating the fitting function of the bathtub curve, an optimization function f(aij) of condition matrix aij is proposed. Entropy-weight method is improved and applied to determine the weights of criteria. Based on the historical operation data, an update method for positive-ideal condition A+ and negative-ideal condition A− is elucidated. To further substantiate the improvement, the proposed methodological model is applied to an online structural health monitoring system for portal crane. Laboratory test and field test have been conducted. Structural strain, inclination, and pitch angle of portal crane are collected. Structural health assessment during lifting, luffing, and turning processes are carried out. The results show that the improved model gets a more stable and effective structural health assessment result, and is favorable for online structural health monitoring system. Thus, the proposed model can be applied to other problems of structural health assessment.

Improved TOPSIS Model and Its Application in Online Structural Health Monitoring System for Portal Crane

It’s very important to monitor the mechanical condition of portal crane for the device safety management. According to the characters of portal crane, a wireless monitoring system of the mechanical condition has been designed in the paper, including the status of metal structure, slewing bearing and speed reducer. The system has solved the temperature drift, zero point setting and other problems of metal structure testing, and GPRS DTUs are used as the core component of the sensors to transfer data to Internet. The monitoring system has the advantages such as simple structure, high precision, low price and great expandability, which has huge application potentiality for the device safety management of Port Company.

Jia Tengfei

Papers

Research on Mechanical Condition Monitoring Technology for Portal Crane by Wireless Sensors