The instability of the tensile armor wire of flexible pipes is a failure mode associated with deep and ultra-deep water applications. Real compressive forces acting on the pipe are necessary to trigger this process. T...The instability of the tensile armor wire of flexible pipes is a failure mode associated with deep and ultra-deep water applications. Real compressive forces acting on the pipe are necessary to trigger this process. The loss of stability may be divided into two distinct processes, according to the main direction of the wire＇s displacement： radial or lateral instability. This study aims at proposing a numerical tool for predicting lateral and radial critical buckling loads for the tensile armor wires of flexible pipes. A simple finite element model, based on springs and beams elements, was developed in ABAQUS~ to deal with this problem in an efficient and reliable manner. A parametric study was conducted concerning the behavior of the critical load when the laying angle, the initial curvature and the total pipe length are varied. The results were consistent with previously published literature data and analytical expressions, proving its applicability to pipe engineering projects. It also has the advantage of approaching the problem three-dimensionally, which allows further modelling modifications, such as including friction effects.展开更多
The present paper gives the design of a new HGMS for magnetic separation of sulphides.The main characteristics of this HGMS are using iron-cladding saddle shaped magnetic coil for instead of the ordinary magnet,and co...The present paper gives the design of a new HGMS for magnetic separation of sulphides.The main characteristics of this HGMS are using iron-cladding saddle shaped magnetic coil for instead of the ordinary magnet,and combining reciprocal-linear motion with vibration to actuate the separation box,and the magnetic field intensity is high up to 2T as well.For improving the magnet system design,a modified finite element method is used to calculate the distribution of magnetic field intensity of separation space of the magnetic coil,and according to the calculation results the magnetic leakage coefficient can be determined easily,thus making designers apart from the empirical way.展开更多
文摘The instability of the tensile armor wire of flexible pipes is a failure mode associated with deep and ultra-deep water applications. Real compressive forces acting on the pipe are necessary to trigger this process. The loss of stability may be divided into two distinct processes, according to the main direction of the wire＇s displacement： radial or lateral instability. This study aims at proposing a numerical tool for predicting lateral and radial critical buckling loads for the tensile armor wires of flexible pipes. A simple finite element model, based on springs and beams elements, was developed in ABAQUS~ to deal with this problem in an efficient and reliable manner. A parametric study was conducted concerning the behavior of the critical load when the laying angle, the initial curvature and the total pipe length are varied. The results were consistent with previously published literature data and analytical expressions, proving its applicability to pipe engineering projects. It also has the advantage of approaching the problem three-dimensionally, which allows further modelling modifications, such as including friction effects.
文摘The present paper gives the design of a new HGMS for magnetic separation of sulphides.The main characteristics of this HGMS are using iron-cladding saddle shaped magnetic coil for instead of the ordinary magnet,and combining reciprocal-linear motion with vibration to actuate the separation box,and the magnetic field intensity is high up to 2T as well.For improving the magnet system design,a modified finite element method is used to calculate the distribution of magnetic field intensity of separation space of the magnetic coil,and according to the calculation results the magnetic leakage coefficient can be determined easily,thus making designers apart from the empirical way.
