Papers by Author: Zhen Zhong Sun

Abstract: The U-bending process of aluminum foam sandwich (AFS) is investigated, and a punch bending test is carried out in this paper. We discussed the bending deformation mode and generated the load & stroke curve of AFS panel by experiments. Macroscopic and microscopic punch forming mechanisms of AFS panels are analyzed by testing experiments and plasticity theory. We study the major deformation defects of AFS forming such as the delamination between the panel and the foam core, the excessive thinning of panels in the round corner, and shear stress cracks of the foam core. A conclusion is drawn on the panels variable blank holder force (VBHF) and the striking block control on the round corner, which would promote the forming technology of AFS.

Abstract: In the context of “Plan for Educating and Training Outstanding Engineers (PETOE)”, which was put forward by the Chinese Education Ministry, we would make great efforts to explore a new training model of practical teaching that face to the “Outstanding Plan”. The new training model will aim at enhancing the students’ practical ability in engineering, innovation ability, and their employment competitiveness. The new training model should be established according to the practical teaching situation of the present higher engineering education and combine the factual condition of our school, what’s more, it also based on the implementation of the “cooperation of colleges and enterprises, combination of work and study” training model of the CDIO (Conceive, Design, Implement and Operate) engineering education.

Abstract: The intent of this survey is to provide general design and operating considerations for the safe and dependable operation of remotely operated hot cell equipment. Hot cell is an isolated shielded room that provides a controlled environment for containing highly radioactive and contaminated material and equipment. Operations within the hot cell are accomplished using master-slave manipulators and overhead crane or electro-mechanical manipulator systems.

Abstract: In this paper, the authors describe a rapid prototyping method to produce vascularized tissue such as liver scaffold for tissue engineering applications. A scaffold with an interconnected channel was designed using a CAD environment. The data were transferred to a Polyjet 3D Printing machine (Eden 250, Object, Israel) to generate the models. Based on the 3D Printing model, a PDMS (polydimethyl-silicone) mould was created which can be used to cast the biodegradable material. The advantages and limitations of Rapid Prototyping (RP) techniques as well as the future direction of RP development in tissue engineering scaffold fabrication were reviewed.

Abstract: In this papers, the authors described a rapid prototyping method to produce vascularized tissue such liver scaffold for tissue engineering applications. A scaffold with interconnected channel was designed using CAD environment. The data were transferred to a Polyjet 3D Printing machine (Eden 250, Object, Israel) to generate the models. Based on the 3D Printing model, a PDMS (polydimethyl-silicone) mould was created which can be used to cast the biodegradable poly (L-lactic-co-glycolic acid) (PLGA )material. The advantages and limitations of Rapid Prototyping (RP) techniques as well as the future direction of RP development in tissue engineering scaffold fabrication were reviewed.

Abstract: The article focuses on analyzing plastic deformation and microstructure evolution mechanism of foam aluminum material when foam aluminum is compressed and stretched uniaxially at room temperature, and studying plastic deformation of foam aluminum at room temperature and high temperature. Results show that cold forming of foam material is restricted by many factors. So, it only carries out some simple integral forming and local plastic forming; High temperature reduces the yield stress and deformation limits of foam material, that the forming can be easily carried out. If parts of TiH2 foam aluminum are processed, the temperature must be below solidus temperature in order to avoiding destructing pore structure.

Abstract: The forming of the completed aluminium foam sandwich (AFS) panels would determine an improvement in the manufacturing of parts and panels. In this paper the authors have investigated the formability of AFS through experiments. the load versus punch stroke curve and deformation procedures of Aluminium foam sandwiche panels was investigated by performing V-bending experiments. A serious problem encountered in the V-bending was bending-induced large transverse shear deformation of the skin-core layer. It causes the delamination of the AFS. It was found from experimental observations that the large shear defomation progresses rapidly only at the final stage of V-bending. Consequently, the air-bending operation for Aluminium foam sandwiche panels is recommended for suppressing the shear deformation of skin-core layer to within an acceptable limit.

Abstract: The surface deflection is an important disadvantage issue in the automobile outer panels forming. It can be controlled effectively through forming process. It is difficult to study the surface deflection because of the complexity of automobile panels. In this paper, a model of cylinder shallow shell is founded, and the measured method and evaluated standard of surface deflection for drawing parts are presented. The influence law of process techniques on surface deflection such as binder force, draw-bead, local force, and shape of blank-hold surface is achieved, which give a basic reference for controlling surface deflection.

Abstract: By using homogenous coordinate transformation principle and Denavit-Hartenberg analysis method, a measurement kinematics model and a error model to arbitrary point of automobile panels in normal mechanical parameter measurement instrument, which the movement of the probe center is relative to machine reference frame is construct. On the basis of using wielding matrix function total differential method, building up the error delivery relation of parameter error of measuring motion model transform to the probe center, and having verified what be built the error model correctness by simulation. The error is enlarge mainly in the process of delivery from angle error, while length error are very minor in error effects. This research can establish a base for studying the measuring-error of portable type measures instrument and it's measuring accuracy.

Abstract: In this paper, a novel algorithm is proposed to detect linear edge. Image gradient is acquired by Sobel or Prewitt filters. Logical addition is applied to enhance image contrast. Statistical method is employed to cope with gradient data—gradient projection in the horizontal and vertical direction to compute the average gradient value. Multi-level B-Spline interpolation is employed to smooth gradient data. At last, edge coordinates can be computed precisely by the number and interval of extreme points. The experiment results are presented to show validity of the algorithm, which precision and accuracy can reach to sub-pixel. The proposed approach puts merits of zero crossing method and threshold method together, which is very robust, convenient and efficient to detect linear edge in industrial environment.