Papers by Keyword: Finite Element Computation

Abstract: Electrical contact crimping is a mechanical fastening process commonly used in aeronautical and aero spatial applications. In order to ensure the perfect electrical conduction and acceptable mechanical properties, the assembly have to fullfil some drastic holding force criteria. This outfit is directly dependent on the indentation depth at the end of crimping. The feedback generally reveals that an over crimping will lead to the cable breakage whereas an under crimping will be characterized by the cable sliding into the contact during pulling. The optimal behavior is a combinaison of both phenomena : the cable must become thinner before slipping into the contact. Numerical simulation is an efficient tool to limit the tedious experimental tests. It is the main topic of our work. This paper deals with prediction of the failure type and the force level required to tear out a contact crimped on multistrand cable for different indentation depths. The determination of optimal crimping condition is determined. In order to simulate the contact tensile test, crimping simulation has to be performed. The first step is then to be able to simulate accurately the crimping stage by using appropriate behavior laws and realistic conditions. One difficulty is linked to the small size of our objects. The first one is a 19 strands cable, in which each strand is about 0.15 mm diameter. The second sample is a 1 mm diameter cylindrical copper contact measuring 7 mm long. Adapted testing devices are described. Geometries and mechanical fields are obtained and then exported in the mechanical holding model to ensure realistic prediction [1]. Impact of crimping conditions on the pulling results is discussed. Pulling simulation results are compared to experimental values. The prediction of breakage mechanisms is also studied. Keywords: Crimping process, mechanical fastening operation, finite element computations, mechanical strength, breakout force, tensile test. [1] Fayolle, S., 2008, Etude de la modélisation de la pose et de la tenue mécanique des assemblages par déformation plastique : application au rivetage auto poinçonneur, Thèse de l'Ecole des Mines de Paris.

Abstract: 260T hot-metal car is a huge shape machinery product used in iron and steel plant for the short distance transportation. The work conditions of the hot-metal car are bad, so the reliability of the product structure must be guaranteed. During the structure design, theoretical study and computer simulation analysis of the car frame are taken using the commercial finite element software. The tests for the 260T hot-metal car product are accomplished by using the modern static testing technology to verify the theoretical calculation. The paper describes the test scheme and field test process, extracts the strain and stress value of key points on the car frame and analyses the test data. At last, the test result data are compared with the finite element computation result data, verifying the theoretical calculation.

Abstract: Developed a device used to assist workover rig in lifting stuck tubing strings from the well during workover treatment, it can create well economic benefit for oil field. The device adopts remote hydraulic control, which is safe and reliable. The structure and work principle of the device is illustrated. The jam release device is mainly made up of hydraulic cylinders, hydraulic pump and hydraulic control valves. With the coordination between lifting hydraulic cylinders and hydraulic slips, the device can lift tubing strings from the well. The important loading unit of the device is analyzed by finite element. The working pressure is made from 5MPa to 20MPa, corresponding to lifting force range of 229kN to 915.6kN, which can meet the jam release force in workover treatment.

Abstract: The two-scale asymptotic expression and error estimations based on two-scale analysis (TSA) are presented for the solution of the increment of temperature and the displacement of a composite structure with small periodic configurations under coupled thermoelasticity condition in a perforated domain. The two-scale coupled relation between the increment of temperature and displacement is established.The multi-scale finite element algorithms corresponding to TSA are described and numerical results are presented.