Applied Mechanics and Materials Vols. 80-81

Abstract: This paper introduces a type of control and test system for internal combustion engine based on Serial bus and virtual instrument technique. It consists of host and intelligent node, with parameter signals communication through RS485 serial bus to form a distributed high-precision status parameters controlling testing system. The host computer implements the user interaction, data storage, status monitoring, power measurement and computation as well as management. The client unit reads the commands of host, controls the rotation speed of engine and excitation current, detects all the parameters of system and transmits the data. The hardware and software structure of the distributed testing system (client) with ATmega128 micro single chip computer and communication module are implemented. And the application software was developed with graphical virtual instrument language LabVIEW. The solution may have some reference value to the design of other internal combustion monitoring system with other control bus and the development of general single chip microcomputer and industrial field monitoring and controlling system.

Abstract: In order to research that how the degree of shear connection influence the static properties of composite beams such as the relative slip on the interface、bearing capacity and failure mode, four prestressed composite beams with different the degree of shear connection were designed, and were loaded on the two symmetric position. The paper described and analyzed the bending behaviors of prestressed composite beam such as the strain distribution of sections、interface slip、deformation and failure patterns on the base of the experimental results. In addition, the paper revised the calculating formulas of the ultimate bending capacity of composite beams with partial shear connection in Eurocode 4 with the least square method combined with test results of domestic and overseas about seven composite beams. The results showed that the correction values were corresponding well with experimental data and the engineering accuracy.

Abstract: In order to ensure the dimensional accuracy of housing with small fillets, various forming factors have been analyzed in this paper based on finite element simulation. Through the analysis of the forming factors, the principle of die angle selection, the proper reverse drawing height in sizing process, sequence of sizing and applications of local sheet bulk metal forming in housing production were put forward, and some forming laws of housing with small fillets were concluded.

Abstract: In this paper, Lg wave records of 43 strong aftershocks in the northern segment of Wenchuan aftershock area recorded by 25 stations of Shaanxi digital network are used. Based on spectral ratio method, a joint inversion method is used to obtain parameters of Lg wave attenuation and site response. In the range of 0.5~7 Hz, the Lg wave attenuation coefficient corresponding to UD, EW and NS components are γ(f)=0.0045f ^0.327, γ(f)=0.0034f ^0.417 and γ(f)=0.0036f ^0.393, respectively. The results show that all stations have site effects lower than 5 in the low frequency, the stations in the Weihe basin as Lint, Jyat and etc do not show obvious amplification, but the stations in the Qinling Mountain show obvious amplification in the high frequencies. At the same time, the results mentioned above are also compared with the that retrieved from small earthquakes.

Abstract: In order to overcome the difficulty of fault detection and clearing in the use and maintenance of a type of rocket mine-sweeping vehicle, the operation principle of fire-control system, the fault characteristics, fault parameters and fault distribution are studied. Furthermore, the fault detection instrument based on embedded system is developed. It consists of hardware and software. The hardware includes of embedded micro-controller STC5A60S2, keyword and highlight LED I/O, LCD, memory circuit, connector-adapter and dedicated connection cable. The dual CPU cooperative technology is also used in the hardware platform. The application software is developed with expert system principle, it runs in two modes of simplified and expert mode. In simple working mode, fire-control fault detection and substitute are performed. However, in expert mode, all the function of system testing, system substitute, fault-clear wizard and parameter management is accomplished. Meanwhile the state machine programming technology is introduced in the software. The instrument brings new ideas how to deduce expert repair in the field, and it has practical value.

Abstract: This paper discusses the configuration and the action principle of a new variable displacement of double-action vane pump, which consists of floating blocks. The floating blocks that may move up and down in accordance with the rotational speed of the pump. The pump belongs to an automotive hydraulic power steering system, and prosperous utilization is expected. The theoretical flow model of the new pump was established and the pump flow changes under different speed were compared.

Abstract: In this paper, in the Walker viscoplastic constitutive model equations are rewritten and the implicit Euler integration form of the Walker model is obtained. Furthermore, using this integration form, the subroutine HYPELA in MSC.Marc software has been coded. The finite element analyses, using subroutine HYPELA have been performed on HASTELLOY-X material, and the comparison between the implicit Euler integration and the explicit Euler integration has been done.

Abstract: Based on the research of numerical simulation of model experiment of water-conveyance tunnel in under soft soil, and three basic types of similarity relation ship between the prototype and the model for dynamic structural model test and dynamic rupture model test was proposed, and the situation where various similarity relation ship is applicable and the technique to ensure similarity for the different goal (to study dynamic behavior, elastic response or damage pattern) was discussed, the similarity relation and the technique is proposed according to specific selection of material of model test . At one time the similarity relation and the technique is validated to pass a example. The results of numerical simulation show: in the specific thing, the similarity relation completely from data of the model test transfer to the prototype. Some new ideas to keep the similarity of the embankment structures are introduced.

Abstract: Extrusion tapping is a novel and important processing method of internal thread, carrying out research on the thread forming process can contribute to a better application of this process in more industrial situation. The principle of extrusion tapping of internal thread is introduced in this paper firstly, and then the simplified finite element model of extrusion tapping and the thread forming simulation is conducted. Next, the thread forming process and metal plastic flow law during extrusion tapping of internal thread are analyzed based on the simulation. Finally, the revised formulas for calculating extrusion deformation area and volume are presented and comparison are made with the referenced formulas, the results show that the revised formulas can express the practical extrusion deformation area and volume more correctly. Furthermore, the similar law between the revised extrusion deformation volume and extrusion force obtained from simulation are proved effectively.

Abstract: There are some deficiencies in the former designed crack monitoring sensor, especially when crack initiates from both sides of hole. To solve this problem, a new scheme of the sensor is presented and corresponding finite element model (FEM) is established. Then the output characteristics of the sensor are analyzed by FEM. It is shown that the sensor is sensitive to cracks, and can be used to monitor the cracks initiating from the edge of the hole, no matter from left or right side. The relationship between crack length and sensor’s output is established by polynomial fitting, and it can be employed in further crack monitoring.