Abstract Application of Pro / Engineer method established Centrifuge Screw conveyor of the solid model and the virtual prototype model, MSC.VisualNastran atmosphere, making use of the finite element method is a kinematic evaluation, modal analysis and static analysis, the screw conveyor bearings at both ends of the mechanical state of the technique multi-order organic vibration frequency, vibration mode and the pressure, strain, displacement and other parameters. According to the simulation results, to check the strength and stiffness evaluation of the spiral conveyor of the major failure modes and harmful position and alterations in leaf thickness spiral conveyor impact strength and stiffness. The outcomes showed that: the current structure can generally meet the style specifications, although leaf thickness is given optimal resolution for the structural design and style of centrifuge useful theoretical reference.
Keywords: screw conveyor structural evaluation virtual prototype finite element blade thickness
CLC quantity: TH237 Document code: A
As the national economy and the speedy development of environmental awareness of the enhanced capacity of the centrifuge, separation efficiency, saving energy, etc. have turn out to be increasingly demanding, how to boost the level of item style and shorten the new solution improvement cycle and accelerate the upgrading of current goods, has become a leading priority. Clearly, the traditional style method , can not meet the new predicament, need to be used, such as optimal style, finite element technique for static and dynamic analysis, Pc CAD and other sophisticated Technologies [two].
Screw conveyor is the primary component Decanter centrifuge, screw conveyor in the static evaluation, primarily based on further analysis and optimization of design and style parameters, to Decanter is of excellent operates in practice. Virtual prototype (VP, VirtualPrototyping) technologies spiral conveyor static, dynamic functionality simulation studies to Pro / Engineer Software program As a platform, the solution of parametric solid modeling, through the establishment of a affordable simplification of the virtual prototype screw conveyor, the finite element approach, the finite element simulation software program MSC.VisualNastran in the spiral conveyor of the kinematic simulation, model simulation and stress, deformation simulation, are multi-stage screw conveyor organic vibration frequency, vibration mode and the pressure, strain and displacement changes, checking screw conveyor to the strength and rigidity of goal, and additional analysis of the spiral conveyor The primary failure mode and unsafe position, primarily based on analysis of the outcomes of the spiral conveyor structure design and style optimization.
1 load and boundary situations 1.1 load Screw conveyor in the major course of their operate load to bear the following three: (1) due to the fact of its high-speed rotation and centrifugal force generated (2) The separation medium (sludge) applied to the spiral blade of the good pressure ( 3) The separation medium (sludge) applied to the friction of the helical blade. Strictly speaking, spiral conveyor gear also bear its own gravity, but Decanter centrifuge with high separation aspect, that is, screw conveyor speed of gravity is far much less than the rotation due to centrifugal force generated, so the calculation and simulation the process, ignored the impact of gravity.
1.two Boundary Circumstances Spiral conveyor within the cylinder as the two ends were connected with the left and appropriate journal, journal bearing about in the drum bearings on the inside cover cavity. Therefore, based on the actual conditions, the model is about supporting the rotation imposed to the constraint.
Spiral conveyor of the strength verify of pressure vessel reference design and style [three]. Screw conveyor of the material as some sort of alloy material, the basic allowable pressure of 20 Sm 3M Pa. As the screw conveyor and the drum of the minimum clearance is 4mm (bilateral), so this evaluation will be 2mm screw conveyor as a study based on the radial deformation.
two Virtual Prototype Modeling and Dynamics Simulation
Virtual prototype is set up with advanced CAD modeling methods consistent with the physical prototype Digital Three-dimensional model, and then use the virtual prototype model of the dynamic simulation. Screw conveyor according to the actual current structure, applications and 3-dimensional Parametric Technology Pro / Engineer  computer software, the establishment of the drum, screw conveyor elements and bearings inside the three-dimensional model, and then simplified as a whole, and the model The Boss, chamfering, bolt holes and other characteristics for processing, does not think about the characteristics of the welding seam . This can save unnecessary constraints, stay away from employing also massive and complex Machine VP model, through the frequent information exchange standard – STEP into the model the finite element simulation application MSC.VisualNastran  in Figure 1, the virtual prototype model, the definition of material, respectively,
Elastic modulus, Poisson’s ratio, density and other related material properties, the definition of speed, pressure and other mechanical parameters getting and sports vice and boundary situations for motion simulation, are screw conveyor and the movement trajectory of the Deputy of the force circumstances in which the each side bearing tension analysis benefits, shown in Figure 2.
3 Modal Evaluation The study is to analyze the spiral conveyor assembles the cost-free mode, the principal parameters of materials constant with the preceding simulation, in which the damping coefficient is .01, total mass 409.0Kg.
As Decanter is a rigid rotor shaft, rotor speed is lower than the 1st order critical speed, so the much more sensible concern is the very first 3 natural frequencies and modes. Taking into consideration its own gravity and boundary circumstances, screw conveyor unit with tetrahedral mesh, the finite element model of a total of 75,430 nodes, 38,451 units, of which the very first 3 modes of tension and displacement in Figure three, Figure 4 stated. Modal evaluation of main final results (see Table 1).
When the screw conveyor in the initial all-natural resonance frequency, the size of the cylinder within the tube (ie axis) and the straight section of the junction of a bigger leaf deformation has apparent bending of the organic frequency also corresponds to the order the crucial speed, by the finite element modal simulation evaluation, the screw conveyor the initial natural frequency is 282.4Hz, the corresponding vital speed for the 13944r/min. As the screw conveyor style speed is 2742r/min, far less than the critical speed, so, screw conveyor speed in the normal range of resonance does not happen.
4 Strength Stiffness Of the screw conveyor to load and full load condition of static evaluation, complete load condition for the good stress, friction, centrifugal force of the linear combination. This is the condition of all the most worthy of concern.
Figure 5 and Figure 6 have been loaded with the tension situation screw conveyor and radial deformation of cloud. In the complete load situation the maximum tension happens at the big finish helical screw conveyor blades start off