Applied Mechanics and Materials Vols. 385-386

Abstract: The conventional precision analysis method of modification and design is qualitative, laborious and time consuming. The precision of reverse parametric modification have direct influences on the quality of the reversed products. In this paper, a quantitative analysis method based on a reverse parametric approach and precision control concept is proposed. Combining with the ATOS scanner system, analyzing every aspect of the precision control and the error distribution, including data acquisition process, reverse reconstruction process and parametric process. In the process of the product reverse parametric modification, general error distribution is mainly composed of data acquisition error, reverse reconstruction error and parametric error. The method of precision control during the reverse parametric modification process is analyzed, according to this method, the total error of parametric modification for die face is 0.089mm, is lower than the accuracy requirement of 0.10mm in the reverse parametric modification process, the reverse modification of the die face of the blade based on precision control is realized. Validity and effectiveness of the method has been confirmed by case studies.

Abstract: Drill tower is the support structure to ensure normal work for drilling, and the structural characteristic has been played a vital role in the stability of drilling rig. In the paper, the 3-D modeling of the drill tower has been established by the software UG and the finite element analysis of the structure has been finished by software ANSYS that it provides a new design method and thought for the new type of electro-hydraulic controlling core drill tower. According to the analysis result, the practicability for the structure is discussed, and furthermore, this study can provide reliable and efficient technical reference for future design of drill tower products.

Abstract: Because a ship model surface (SMS) is a large symmetrical freeform surface (LSFS), the machining efficiency and precision of current handcraft method is very low. According to the shape characteristics of SMS, this paper adopted symmetrical machining (SM) technology to manufacture SMS, solved the collision of cutters or headstocks in SM process, proposed the machining solutions for symmetrical machining residuals (SMR), divided the manufacturing process to SM stage and SMR stage, and planed the tool path respectively. The real machining results of a twin-skeg SMS, which was machined by a 4-axis SM machine tool, conforms that the SM can reduce the SMS machining time from 60 workdays needed for handcraft method to 7 hours, and the machining precision and surface fairness are also improved obviously.

Abstract: One of the main logistics function is handling and transporting which happens with very high frequency in the logistics system and occupies an important part of logistics cost. An automated handling system, such as shelves manipulator bracket, is quite necessary because of its cost of large manpower and time. According to the software Solidworks, the model of the shelves manipulator bracket can be established and analyzed by the plug-in of COSMOS Works. The loads and boundary condition of the bracket is calculated through the actual situation, and the stress characters has been obtained as soon as pretreatment is done. The FEA method that used by Solidworks has provided a new though about logistics devices.

Abstract: The structure of inner cylinder component of drum washing machine has a critical impact on its working performance and service life, as a result, the structure analysis of the drum assembly (spider and main shaft) is chosen to be the research object in this paper. As the three-dimensional model is established by PRO/E, the structure intensity characteristic has been analyzed with the method of finite element analysis which is based on software Ansys/Workbench. According to the stress distribution characteristic, the maximum stress value that the spider has been bearing can be contrasted and analyzed with different load which can make sure the periodic properties of structure loads. The analysis and optimization method based on Ansys/Workbench provided a new thought which had the guiding significance for the development of new products of drum washing machine.

Abstract: Rear sub-frame is one of the important parts of automobile chassis. Tube hydroforming (THF) is a kind of the advanced manufacturing technology to produce the sub-frame. The success of a THF process is highly dependent on the loading paths (axial feed versus pressure) used. The uniform design method combined with the response surface method was used to optimize the loading path in this paper. The results obtained by numerical simulation demonstrated that product quality is good in the optimized loading path.

Abstract: With the development of drilling technology, rotary drillstring not only produces random multi-directional collisions with the inner wall of pipe, also couples with the inner and outer annular fluids. This results in a complex system of nonlinear fluid-structure interaction. In the paper, structure and mode of operation about rotary drillstring are considered, the equations of the structure dynamics, fluid equation of continuity and momentum equation are coupled. The three-dimensional numerical model and computational method is established about the fluidstructure interaction dynamic analysis of rotary drillstring. Take the rotary drillstring and inner and outer fluids as a research object, dynamic analysis of the rotary drillstring is finished, considering the fluid-structure coupled characteristics and compare the air medium, the results show the effect of fluidstructure interaction. It can provide the feasible method for the study of the string in the oil drilling and production engineering and conduct the development of drillstring dynamics in horizontal well drilling engineering.

Abstract: In order to reduce the cylinder work force on pull tower linkage of self-erecting tower crane, the geometric parameters of hinge points about linkage mechanism were optimized. Through the force analysis to whole system of bar linkage, the cylinder force of bar linkage is regarded as optimization objective function, and the geometric parameters of working devices hinge points are used to variables, then, the optimization model is established. The optimization design is conducted based on the fmincon function of MATLAB optimization toolbox. The curve about force of the cylinder with the towers rotation angle variation can be obtained. Comparison of the results before and after optimization is showed that the maximum force of cylinder is reduced 11.5%. It is shows the optimization method is quickly and effectively. The results of parameter optimization improve the working performance of the self-erecting tower crane.

Abstract: With respect to the conventional coupling thread, the coiled tubing had the advantages of without screwing on and screwing off in the lifting pipe string. It was widespread used in the drilling and repairing well. According to the actual state of the coiled tubing, the mechanical models on the ground and in the wellbore were established in this article. The were able to simulate the contact state of the coiled tubing through the drum, the guide frame, the injector head and in the wellbore. The curves of the axial force that through the rollers, guide frame, injection head and wellhead was obtained with the changes of the depth.

Abstract: According to the working principle and structural feature of compressive packer, mechanic analysis of rubber tubes was done with adopting Mooney-Rivlin model. The contact stress between rubber tube and the casing and axial compression distance were figured out at 83MPa of the differential pressure between inside and outside string. The results show that the middle tube has the function of beginning to set the paker and the lower tube seals and separate the layers. Upper tubing should be installed the equipment to prevent shoulder protruding.