[en] An analytical model for current–voltage behavior of amorphous In-Ga-Zn-O thin-film transistors (a-IGZO TFTs) with dual-gate structures is developed. The unified expressions for synchronous and asynchronous operating modes are derived on the basis of channel charges, which are controlled by gate voltage. It is proven that the threshold voltage of asynchronous dual-gate IGZO TFTs is adjusted in proportion to the ratio of top insulating capacitance to the bottom insulating capacitance (C_TI/C_BI). Incorporating the proposed model with Verilog-A, a touch-sensing circuit using dual-gate structure is investigated by SPICE simulations. Comparison shows that the touch sensitivity is increased by the dual-gate IGZO TFT structure. (paper)

[en] Welding has become the main processing method of the supporting structures on tracked vehicles. The accurate evaluation of fatigue life of welding structures is of great significance significant to the reliability of tracked vehicle. The whole analysis process, based on strengthened load spectrum and structural stress method, is proposed in the study to predict the fatigue life of welding structures. Initially, the road-load spectrum of different conditions was obtained by vehicle tests. Then, the data which had been preprocessed were compressed based on pseudo-damage editing. Furthermore, the load spectrums were extrapolated and equivalent to program-loaded spectra according to the non-parametric rain-flow extrapolation method. On the other hand, the finite element model of the welding structure of the tracked vehicle was established to calculate the structural stress at the welding seam (paper)

[en] Cone seal structure is widely used in metal tube connection of industrial equipment and ground vehicle. In vibration environment, the leakage failure of cone seal occur frequently, which will affect the function and reliability of the product directly. In this paper, the contact stress for typical cone sealing structure in low pressure metal tube under vibration loading is analyzed and the mechanism of liquid leakage failure is discussed using the finite element numerical method. Results show that the circumferential contact stress distribution is uneven on the interface of cone sealing structure under the cyclic load introduced by local vibration. The contact stress is significantly lower than the initial pretension stress in some areas, which will result in the leakage failure of cone sealing structure. (paper)

[en] The ball hinge is a key component of the vehicle chassis that connects the steering knuckle and the control arm. This study analyzed the multiple failure behaviors of the chassis ball hinge. First, according to the macroscopic failure characteristics of the ball hinge, the analysis method of the fault tree was adopted to identify the possible cause of the failure. The axial force and radial force of the ball joint were obtained by simulating the force of the vehicle under the typical extreme conditions. The stress distribution of the ball pin was obtained by finite element analysis of the ball joint. The calculation results are consistent with the fatigue crack position of the ball hinge. Then the ball hinge was disassembled. On the one hand, the macro morphology was observed. On the other hand, the chemical composition and microstructure of the ball pin material were analyzed by scanning electron microscope and infrared spectrum analyzer. Finally, the macro morphology and microstructure of the ball joint seat, ball bowl, dust cover and other parts matched with the ball hinge were analyzed to further verify the failure reason of the ball hinge. The results showed that the dust cover of the ball hinge was firstly aged and cracked, and the external dust and particles enter into the friction contact area of the ball hinge, which caused the ball pin and ball bowl to be stuck. During the driving process of the vehicle, the ball pin undergoes unidirectional bending fatigue fracture in the stress concentration area at the root of the conical surface. (paper)