Advanced Materials Research Vols. 538-541

Abstract: In signal cylinder diesel engine we often use dual shaft balance mechanism to balance reciprocating inertia force produced by the piston and moving parts, and reduce vibration of diesel engine. For this paper, the model crank -connecting rod and balance mechanism of a signal cylinder diesel engine were built in simulation software ADAMS. Piston’s movement law and its force curve have got through multi-body dynamics simulation to the model .By further processing to the simulation results, we got curves of piston’s reciprocating inertia force and balance shaft’s balance force. Comparing the two curves, we got the following conclusions: the difference between positive and negative peak for reciprocating inertia force that haven’t balanced was about 5500 Newton, which was equal to around 34% of the difference between the positive and negative peak for reciprocating inertia force, and the main reason for this is the dual shaft balance mechanism only balanced one step reciprocating inertia force; Though the balance effect was quite obvious, for ideal conditions there is a difference, and further improve can be done.

Abstract: According to the requirements for field work in precision agriculture, a new wheeled terrain adaptive locomotion theory with two-degree-of-freedom basing on the conventional wheeled locomotion mechanism is presented for the farmland environment in rough terrains of hill, mountain, and etc area. The mechanism’s two-degree-of-freedom of terrain adaptive locomotion is calculated when running on uneven terrain area. This research is valuable and helpful in theory for improving the agricultural machines’ terrain adaptive locomotion ability.

Abstract: The main research of planar two-DOF hybrid-driven robot is on the planar five-bar and the seven-bar mechanism, the planar two-DOF seven-bar mechanism is taken as the research object in this paper, the Assur Groups transformation method is used for the forward kinematics analysis of this seven-bar mechanism. The mathematical model of this mechanism is established for the forward kinematics analysis, and the COSMOSMotion is used for the kinematics and dynamics simulation of this hybrid-driven seven-bar mechanism.

Abstract: In lifting, remoted operated dive vehicle（ROV） may swing with the effect of wave. Based on the general form of Lagrange’s equation, a 3-DOF nonlinear swing motion kinematic model was set up. The kinematic response was studied using methods of numerical simulation. The results demonstrated that the kinematic response depends on the length of cable, lifting speed and excitation frequency. Conclusions drawn from this work can be used for safety assessment and theoretical basis for lifting ROV.

Abstract: This paper presented a real-time measuring method of temperature fields and thermal deformations in vertical machining center. And a FEA model including the thermal contact resistance at interface for evaluating the temperature distribution and tools deformation in vertical machining center (VMC) was established. Compared with the experiment results, it is shown that the new model is much more accurate than the traditional model without considering thermal contact resistance at interface.

Abstract: Trunk assembly is an important opening and closing part of the car body，its design must be considered rationality of the trunk’s rationality, convenience, comfort and other factors, so there are certain difficulties in the design. This paper is based on the luggage’s design principle and basic performance requirements. And this paper also makes full use of ergonomics and makes a number of SAE dummy simulation to determine the best hinge type of the trunk lid.

Abstract: On how to properly choose initiation position and parameters of cavity liner structure of multi-mode penetrator shaping. Combine gray relation analysis with simulation of different ways of initiation and different cavity liner structure, we analyze the effect of ways of initiation, the height of cavity liner, height ratio of cone and thickness of cavity liner on forming parameters of shaped charge. We get the sequence of factors which affect the penetrator molding effect. That is charge initiation position>the height of cavity liner>cone height ratio of cavity liner> thickness of cavity liner, which provide a reference method for optimization design multi-mode warhead.

Abstract: Bike helmets must meet minimum standards of construction and materials design. This paper focuses on assessment of a helmet based on the shock absorbing test of CPSC’s standard. Computer simulation finite element model is an economical and time-efficient alternative to physical testing. By those compelling reasons, a finite element model of helmeted headform is constructed to serve for development of bicycle helmet technologies. This study performs finite element analyses of helmet impact tests using LS-DYNA software. The linear accelerations at center of gravity of the headform are measured in this simulation. This study implies that the numerical method is a practical approach to helmet design problems. Furthermore, the helmet test model proposed here has potential for guiding the future development of helmet technologies.

Abstract: The joint of the toolholder-spindle is the most weakness structure in the system of toolholder-spindle. It affects the manufacturing efficiency and the surface quality of work piece. It is important to identify the dynamic contact parameters for evaluating the connectivity of the toolholder-spindle system. The article introduces an approach to identify the dynamic contact parameters of toolholder-spindle joint base on frequency response function (FRF). Using the BT40 toolholder-spindle system, we can get the dynamic contact parameters curve of toolholder-spindle by the previous approach. The translational and rotational contact parameters can be obtained by sensitivity analysis. By comparing the simulation results with those of experimentation, it can prove the validity of identified dynamic contact parameters. The research results can provide a theoretical basis for the optimization of toolholder.

Abstract: This paper, starting from the concept and definition of fractal dimension, discussed the properties and established the sufficient and necessary conditions of the fractal dimension estimate model of spatial objects such as lines, facets and volumes. Based on the conditions, we put forward a fractal dimension estimate model for linear spatial objects, and verified the rationality and validity of the model for linear objects’ fractal calculation.