In this article, we present the design of the suspended stripline low‐pass filter (LPF) with finite frequency transmission zeros for enhancing band‐edge roll‐off and increasing stop‐band signal rejection levels. The proposed LPF is a seventh‐order circuit which exhibits two transmission zeros in the stop‐band region. The LPF has achieved the benefits of size compactness, low dispersion, high immunity to the noise inference, and low insertion losses. An equivalent circuit model composed of lumped elements is developed to predict filter's characteristics, and ultimately it is used to calculate the LPF's frequency responses during the design. The equivalent circuit model is used to accelerate the proposed LPF design in the early stage with its calculated data validated by a commercial electromagnetic software simulation. Experiment is conducted to verify the LPF's design and its performance. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:297–301, 2014

Abstract. In light of the complex and non-stationary characteristics of misalignment vibration signal, this paper proposed a novel method to analyze in time-frequency domain under different working conditions. Firstly, decompose raw misalignment signal into different frequency bands by wavelet packet (WP) and reconstruct it in accordance with the band energy to remove noises. Secondly, employ empirical mode decomposition (EMD) to the reconstructed signal to obtain a certain number of stationary intrinsic mode functions (IMF). Finally, apply further spectrum analysis on the interested IMFs. In this way, weak signal is caught and dominant frequency is picked up for the diagnosis of misalignment fault. Experimental results show that the proposed method is able to detect misalignment fault characteristic frequency effectively.

The innovative hybrid impact hydroforming (IHF) technology use high energy forming complex parts in very short time which can improving forming quality of hardforming materials like Aluminum alloy widely used in automotive and aircraft industries. The impact hydroforming technology means the most features are formed by hydroforming and the small features are rapidly reshaped by high intensity impact energy in a very short time after the traditional hydroforming. Thus, the impact energy is the most important parameter of Innovative Hybrid Impact Hydroforming. Using numerical simulation software MSC.PATRAN/DYTRAN, the whole system of hybrid impact hydroforming apparatus was analyzed. The initial gas pressure and the mass of hammer directly affect the energy efficiency. The results show greater initial gas pressure will linear increase the energy output. Moreover, the bigger mass of hammer will reduce the velocity of hammer, but it still increase the energy output. Therefore, the research is very useful for improving energy efficiency of IHFand widing its application.

The angular misalignment of a three-point supported dual-span rotor system is discussed. Vibration measurement for coupling misalignment is taken in this paper by using the model test rig, and the rotor vibration response characteristics with different misalignment quantities and different rotating speed are compared. Based on the finite element method, researches on the three-point supported dual-span rotor system are made, and then the simulation and experimental results are compared. Both the simulation and the measurement are compared to show the features. The results show that the amplitudes of the misaligned rotor vary with rotating speeds and misalignment angles, and the center orbits of the misaligned rotor change into ellipses with the increase of misalignment, together with double harmonic responses.