Contact Stiffness Determination of High-Speed Double- Locking Toolholder-Spindle Joint based on a Macro- Micro Scale Hybrid Method

Yongsheng Zhao,Jingjing Xu,Ligang Cai,Weimin Shi,Zhifeng Liu,Qiang Cheng 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.6

The stiffness of toolholder-spindle joint at high speeds plays an important role in the cutting efficiency and the machining accuracy. A double-locking toolholder (BTF type) is designed to improve the stiffness of joint. This paper presents a macro-micro scale hybrid method to determine the stiffness of double-locking toolholder-spindle joint at high speeds. In this method the finite element method and the three-dimensional fractal method are combined. It is assumed flat in macro-scale for the contact surfaces of joint. The finite element method is introduced to obtain the pressure distribution with the influence of centrifugal force at high speeds. In micro-scale, the contact surfaces are fractal featured and the three-dimensional fractal method is used to compute the stiffness based on the pressure. Experiments with BTF40-type toolholder are conducted to verify the efficiency of the proposed model in zero-speed case. The relationship between the stiffness and the technological parameters of the system can be derived based on the presented model. The upper limit of speed, the optimized range of each technological parameter are determined for obtaining the higher stiffness of joint. The results can provide theoretical basis for improving the cutting efficiency and the machining accuracy of high-speed machine tool.

Dynamics of waste-to-energy incineration R&D collaboration networks: a social network analysis based on patent data

Ding Ma,Yongsheng Yu,Si-shi Liu,Ya-rui Zhang 한국자원공학회 2017 Geosystem engineering Vol.20 No.2

The municipal solid waste in China is increasing at an unprecedented pace due to the upgrading urbanization and improving living standard. The waste-to-energy (WTE) incineration technology offers a viable and potentially profitable technical solution to this booming phenomenon. The highly complex and systematic nature of WTE technologies have led to the emergence of WTE innovation network in the past decade. This study applies complex network theory as well as social network analysis to investigate the social network structure evolution of WTE technologies in terms of global network properties, major actors’ centrality and collaboration relationships. Based on the data-set covering joint filing patents pertaining to waste heat over the period 2006–2015, this study finds that the overall WTE innovation network exhibits the properties of scale-free network with minority organizations linking to abundant organizations. A large fraction of major actors represent the first-movers in the WTE research and still control the technological trajectories. The collaboration relationships have moved toward higher level of multidisciplinary and larger technological distance. Overall, the evolution of WTE innovation network features a young state of industry with high regime dependence. Finally, some suggestions are proposed to shed light on benign development of WTE innovation network.

Effect of non-thermal plasma injection flow rate on diesel particulate filter regeneration at room temperature

Chen Xulong,Shi Yunxi,Cai Yi-xi,Xie Junfeng,Yang Yinqin,Hou Daolong,Fan Yongsheng 한국탄소학회 2024 Carbon Letters Vol.34 No.3

For the regeneration of diesel particulate filters (DPF) using non-thermal plasma (NTP), both cost-effectiveness and regeneration efficiency should be raised. This study compared and contrasted the physicochemical characteristics of carbon black and engine particulate matter (PM). After carbon black was put into the DPF, an experimental setup for the oxidation of PM using NTP was created. The findings showed that carbon black and PM samples had comparable oxidation traits, micro-nanostructures, and C/O elemental ratios. O3, the main active species in NTP, was susceptible to heat breakdown, and the rate of decomposition of O3 increases with increasing temperature. The removal effectiveness of carbon black first improved and subsequently declined with an increase in the NTP injection flow rate during offline DPF regeneration using NTP at room temperature. A relatively high carbon black removal efficiency of 85.1% was achieved at an NTP injection flow rate of 30 L/min.

Dynamic Performance and Stress Wave Propagation Characteristics of Parallel Jointed Rock Mass Using the SHPB Technique

Qirui Wang,Erxiang Song,Peng Xu,Yongsheng He,Xiaoyan Shi,Huanzhen Xie 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.5

To investigate the effects of joint number on dynamic compressive strength, crushing effect, stress wave propagation, stress wave conversion, and energy evolution of rock masses, SHPB and LS-DYNA were used to conduct impact experiments and numerical simulations, respectively. The results demonstrate that the dynamic strength of a multi-jointed (two- and three-jointed) rock are 11.1 and 25.1% lower, respectively, compared with that of a single-jointed rock. The weak surface near the joint causes the rock mass to crack first. The rock cracking time advances significantly as the joints number increases. The reflection coefficient falls as the number of joints increases, because the wave impedance of the joint differs from that of the rock. The transmission coefficient, however, is exactly the reverse. When the P wave strikes the specimen, the vibration direction of the particles is deflected at the joint, resulting in a shear wave. P waves are reflected and superimposed between joints, increasing the strength of shear waves and resulting in more transverse cracks in multi-jointed rock masses under dynamic loading. Meanwhile, the total energy consumed by a bedrock under dynamic loading is obviously larger than that of joints. However, the total energy absorbed by joints exceeds that of the bedrock when the joints number increases. The results further enrich the dynamic basis of jointed rock masses.

Impact of Natural Gas Fuel Characteristics on the Design and Combustion Performance of a New Light-Duty CNG Engine

Han Zhiyu,Wu Zhenkuo,Huang Yongcheng,Shi Yongsheng,Liu Wei 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.6

A study on the design and combustion performance of a new spark-ignition compressed natural gas (CNG) engine for light-duty automotive applications was carried out. The effects of natural gas fuel characteristics on engine design were analyzed in guiding the design of the engine. One-dimensional simulations with added natural gas laminar flame speed data were conducted in upfront to optimize the engine performance with the evaluation of the effects of compression ratio (CR), intake variable valve timing (VVT), and spark timing, etc. The results were validated through engine dyno experiments. It showed the CNG engine’s torque and BSFC could be increased by from 5.2 to 6.6 %, and from 4.6 to 5.7 % , respectively, with increasing the CR from 10.5 to 12. At full engine loads, the intake VVT angles needed re-adjustments for improving the torque output, while the original gasoline-engine adapted VVT resulted in the optimal BSFC under other operation conditions. In additional, the transient emission characteristics of a passenger car powered by the CNG engine were also presented. The CO2 emission of the vehicle under NEDC is 117.32 g/km, which meets China’s 2020 CO2 limit. When equipped with a three-way catalyst, the vehicle can meet the China 6b emission standard.

Bioinspired Fabrication and Evaluation of Molecularly Imprinted Nanocomposite Membranes with Inorganic/Organic Multilevel Structure for the Selective Separation of Emodin

Chao Yu,Jian Lu,Qi Zhang,Hougang Fan,Minjia Meng,Shi Zhou,Yinhua Jiang,Yongsheng Yan,Yilin Wu,Chunxiang Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.2

High purity emodin is in great demand with the development of medical treatment. Molecularly imprinted membranes (MIMs) have gained wide attention for selective separation of emodin due to its preferable selectivity. In this work, we describe a simple two-step method for developing emodin-imprinted TiO2@CA (ETMIMs) and emodin-imprinted SiO2@CA (ESMIMs) based on organic–inorganic nanoparticle (SiO2/TiO2) modified cellulose acetate membranes at room temperature. SiO2/TiO2 is used to improve the structural stability and roughness of membranes, and dopamine is used as the functional monomer and crosslinker. Importantly, the as-prepared membranes not only exhibited enhanced rebinding capacity (ETMIMs = 30.73 mg g -1 and ESMIMs = 46.04 mg g -1) but also possessed superior rebinding selectivity (2.76 and 2.99 for physcion and 2.42 and 3.30 for aloe emodin onto ETMIMs and ESMIMs) as well as permselectivity (7.59 and 6.69 for physcion and 5.94 and 5.78 for aloe emodin onto ETMIMs and ESMIMs). The regeneration ability of ETMIMs and ESMIMs still maintained 90.4% and 89.2% of the original rebinding capacity after 10 cycling steps, respectively. The ETMIMs and ESMIMs obtained in this work show potential applications for selective separation and purification of emodin from analogs.