Papers by Keyword: Deformation Analysis

Abstract: A commercially available laser marking system based on diode-pumped Nd:YVO₄ laser was used for creating grid patterns for forming strain analysis of three different multiphase steels. The aim was to determine and analyze the influence of laser working parameters on the formability of the investigated sheet materials by means of an in-depth characterization of this induced microstructural and geometric inhomogeneity. The electrochemical etching served as the reference method without the negative effect of generating inhomogeneity. The formability was evaluated using the cupping test according to Erichsen. While the quantification of geometric inhomogeneity was based on the determination of the notch factor, microhardness measurement was used for the evaluation of micro-structural inhomogeneity. The results showed that multiphase steels exhibit similar values of the mark depth under the same creating parameters by means of laser. Furthermore, only the induced geometric inhomogeneity had a marked influence on the material formability. Finally, a method for the prediction of the optimal values of the grid pattern mark depth was developed from the perspective of its good visual recognizability and associated with the microstructure based material sensitivity to stress concentrators.

Abstract: To overcome the defect that the support pressure is required to be measured or supposed in elasto-plastic analysis in strain-softening rock mass, by the connection of the support pressure imposed on surrounding rock mass, without assuming the support pressure is known a priori, an improved model of solving plastic radius and the distribution of radial displacement around the circular tunnel is proposed. Based on Hoek-Brown yield criterion, the results obtained by strain-softening model are compared with those of elastic perfectly brittle and elastic perfectly plastic models. The examples reveal that the difference of plastic radius obtained by the three models is comparatively smaller, but the difference of radial displacement is comparatively larger. The proposed model overcomes some defects of the previous studies in deformation analysis for tunnel.

Abstract: After the introduction of the ANCOLD Guidelines on the dam design to withstand earthquakes in 1998, many dams in Australia have been reviewed on their capacity to withstand earthquakes. As results, many of them have been upgraded in the last two decades to increase their resistance against seismic loading. This paper presents the current methods used in Australia to undertake seismic upgrade for earth dams. The paper firstly presents brief discussion on the current methods of seismic stability assessment of earth dams. It then discusses the advantages and limitations of the available methods for seismic rehabilitation. Finally, it presents one of the case histories of seismic upgrade in Victoria, Australia.

Abstract: Fiat 500 L tailgate was manufactured from innovative 3D functional textile – long glass fibre reinforced polyester thermoformed composite as a demonstrator within 3D Light Trans project of the EU 7^th Framework Programme. Unlike the second demonstrator, Bentley spare wheel well and battery case, the Fiat tailgate was characteristic by not negligible external loading and so, the strain and deformation behaviour had to be experimentally verified as the last step of the project implementation. Capabilities of the material for efficient manufacturing of different types of complex components were demonstrated. The tailgate provides an innovative high strength, low weight alternative to the nowadays customary metal parts manufactured with state-of-the-art technology. The experimental method and results are described in the paper.

Abstract: In the paper are presented some experimental and by simulation results obtained in the machining by milling of plane surfaces of thin walls parts. Two case studies are considered: when the thin wall is vertical and then the thin wall is horizontal positioned. Some values of the cutting force components are established using a modern dynamometer and a data acquisition system. The elastic deformation values of the machined part are also determined by experimental tests and simulated in a FEM analysis. Depending on the data that geometrically define the part and the cutting tools, their materials and the cutting parameters, are set values of the cutting forces and powers. There are presented the results of values comparison obtained by measuring during the processes with those established by applying FEM. Both case studies results lead to some remarks and useful recommendations for determining the machining parameters and the needed conditions for the technological system in the processing of parts with thin walls and minimum deformations.

Abstract: A reliable flanges for steering racks of a Mars rover prototype needs the structural analysis of detail design. This paper presents the static analysis result from a FEA (finite element analysis) software. We set the preloading force of screwed connection and the load of vehicle on the flange. The result of analysis shows the extent of deformation is within the acceptable range and the permanent deformation and fracture does not happen.

Abstract: To study the effects of deformation on bridges, the finite element analysis method was used. The railway   continuous curved rigid frame bridge has been taken into account. Both the deadweight, prestress, and creep of the concrete were used for comparative analysis about the effect on displacement and twisting angel, then some practical application conclusions were obtained. The maximum reaction values were produced in different sections under the extreme cantilever stage and the finished bridge stage. Futhermore, the study of structural spatial behaviors is of great importance.

Abstract: After a literature survey, the application of 3D seepage-consolidation coupling FEM model based on Biot theory and Cam-Clay model for simulating deep excavation dewatering in soft soil is studied. A foundation pit in East-China is taken as an example and 3D finite element method is used to simulate the dewatering and excavation. Through the 3D finite element analysis, the three-dimension numerical method can be applied to study the deformation behavior of foundation pit and surrounding soil. The numerical simulation experience and data presented in the paper can be refereed in the design, construction and research of similar projects.

Abstract: To research the deformation of the net surface of the mesh antennas under the gravity, a calculating model of a large hoop truss mesh antenna was studied using the whole coordinates interaction method (WCIM). The influence of the gravity and the initial tensions in the networks on the surface accuracy of the mesh antennas was discussed. To calculate the surface shape in the agravic environment, a cup-up and cup down procedure was developed. The influence of the gravity on the surface accuracy decrease when the initial tensions in the networks increase. When the angle between the antenna and the horizontal plane (AAHP) varies, the nodes of the net surface fluctuate in the certain ranges respectively in the local coordinates fixed on the antennas. The conclusions are useful for the adjustment for the net surface accuracy on the ground.

Abstract: Since the bracket deformation caused by its deadweight is too large, and the riveting of aircraft panel is always over-tolerance, a new algorithm for analysis and compensation of bracket deformation is presented in this paper. The algorithm is formed by combining finite element (FE) simulation with analytic method, which is fit for different combinations of supporting plates of bracket system. The formula is constructed through cubic spline interpolation and envelope surface fitting according to the FE simulation data. Meanwhile, a corresponding compensation method is proposed. Finally, a numerical simulation example with the software of ABAQUS shows that the algorithm and its results are valid and feasible.