An Experimental Study of Damage Detection on Typical Joints of Jackets Platform Based on Electro-Mechanical Impedance Technique

Abstract

Many methods have been used in the past two decades to detect crack damage in steel joints of the offshore structures, but the electromechanical impedance (EMI) method is a comparatively recent non-destructive method that can be used for quality monitoring of the weld in structural steel joints. The EMI method ensures the direct assessment, analysis and particularly the recognition of structural dynamics by acquiring its EM admittance signatures. This research paper first briefly introduces the theoretical background of the EMI method, followed by carrying out the experimental work in which damage in the form of a crack is simulated by using an impedance analyser at different distances. The EMI technique is used to identify the existence of damage in the welded steel joints of offshore steel jacket structures, and Q345B steel was chosen as the material for test in the present study. Sub-millimetre cracks were found in four typical welded steel joints on the jacket platform under circulating loads, and root average variance was used to assess the extent of the crack damage.

Efficacy and Damage Diagnosis of Reinforced Concrete Columns and Joints Strengthened with FRP Ropes Using Piezoelectric Transducers

“…Regarding the frequency response of the PZT 1 transducer (see also Figure 15 ) relatively slight discrepancies could be detected between the curves representing the examined loading steps and the baseline curve (healthy state) of the structural member. Similar decays between the frequency response curves of the used PZT were also produced in relative experimental studies conducted by the authors in [ 56 , 57 , 61 , 62 ] and other researchers in [ 65 , 66 , 67 ]. This fact indicates that there were no significant changes in the material state in the neighborhood of the attached transducer, and, therefore, no considerable damage or cracking was detected in the concrete of the beam near its conjunction with the joint by the SHM measurement of PZT 1.…”

Design and Simulation of Small-Scale Waste Separation and Sorting Equipment

“…Q345 steel was used for construction of the base [26,27]. The density of Q345 steel was 7.86 g/cm 3 , the elastic modulus was 209 GPa, the Poisson's ratio was 0.29, and the tensile strength and the yield strength were 620 MPa and 345 MPa, respectively [28,29]. The material properties are listed in Table 1.…”

Review on Fixed and Floating Offshore Structures. Part II: Sustainable Design Approaches and Project Management

“…One of the most obvious of these applications is offshore oil production, which presents a substantial challenge to the product designer or offshore engineer [81][82][83]. Environmental loadings [84][85][86][87][88], hydrodynamics [89][90][91][92][93][94][95][96], hydroelasticity [97], corrosion [98], failure analysis [99], ocean wave mechanics [100][101][102][103][104][105][106][107][108], fluid content loadings [109][110][111][112][113][114][115], fatigue limits [116][117][118][119][120], reliability [121][122][123][124][125][126][127][128], and so on are all factors to consider ...…”