Nonlinear dynamic analysis of cutting head-rotor-bearing system of the roadheader

Zhilong Huang,Zhongchao Zhang,Yiming Li,Guiqiu Song,Yang He 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.3

In order to study the dynamic characteristics of cutting head and cantilever system, a nonlinear dynamic model with a 13 degrees of freedom (13-DOF) lateral torsional coupled cutting head-rotor-bearing system (CHRBS) is established. The nonlinear coupled factors of spline clearance and bearing contact force are mainly considered, the dynamic analysis of CHRBS under time-varying load is carried out. The results show that there is no positive correlation between the cutting rock thickness and the states of chaotic motion and quasiperiodic motion. The system is in the two states mentioned above when in low speed region. With the increase of rotational speed, the chaotic motion becomes periodic motion. When the hardness of rock is lower, increasing rotational speed can reduce the vibration of the system, and the cutting thickness can be increased to improve the productivity and lump rock rate. As the hardness of rocks increases, the coupled system shows complex dynamic characteristics when the rotational speed changes from low to high, and the vibration increased. When cutting hard rock, the cutting speed should be increased. However, when the speed is too high, the cutting torque of system becomes smaller. In the case of cutting hard rock, reasonable rotational speed should be chosen between improving stability and increasing cutting force. The dynamic analysis results provide strong support for the vibration reduction and dynamic design of roadheader.

Online Safe Flight Envelope Protection for Icing Aircraft Based on Reachability Analysis

Zhilong Yu,Yinghui Li,Zhe Zhang,Wenfeng Xu,Zehong Dong 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.4

Icing encountered by an aircraft in flight can pose a great threat to flight safety, which is the foremost concern in aviation. Ice accretion has nonlinear and coupling properties, and therefore, a conventional envelope protection system cannot successfully deal with the condition. A safe flight envelope based on reachability analysis is proposed in this paper as a basis for designing an online envelope protection system for aircraft under icing conditions. This system uses a neural network method to identify changes in the aerodynamic coefficients and to classify the degrees of icing and uses a database-driven approach to solve the onboard safe flight envelope computation problem. The database of icing safe flight envelopes is created offline and can be retrieved in real time. The Research Civil Aircraft Model (RCAM) encountering icing conditions in the climbing phase was taken as an example to verify the feasibility of the online safe flight envelope protection system. The simulation results showed that the system can classify the degrees of icing efficiently, prevent the aircraft from deviating from the safe flight envelope, guide it back to the envelope along the fastest path, and reduce the risk of loss of control under icing conditions.

Effectiveness of Ionic Polymer Soil Stabilizers on Warm Frozen Soil

Zhilong Zhang,Hu Zhang,Jianming Zhang,Mingtang Chai 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

Warm frozen soil has characteristics such as low shear strength and high compressibility. To improve its mechanical strength, the ionic polymer soil stabilizers (IPSS): named XRH stabilizer and acid cation exchange resin (CER) were adopted for reinforcing the warm frozen soil from the Beiluhe region of the Qinghai–Tibetan Plateau. To evaluate the effects of IPSS on warm frozen soil and analyze the mechanisms responsible, measurements were made of the physical, chemical and mechanical properties of warm frozen soil, both untreated and following treatment with IPSS. The addition of IPSS to the soil resulted in a significant decrease in the plasticity index, freezing temperature, and cation–exchange capacity of soil. The warm frozen soil were reinforced with XRH and CER, the cohesion increased by 87.9% and 43.1%, respectively, and the compressibility decreased by 44.5% and 41.1%, respectively. The trends of mechanical strength and unfrozen water content of reinforced warm frozen soil were the same, with extreme values being observed in response to treatment with an IPSS content of about 1% (optimal proportion). In addition, the curing mechanism of IPSS on warm frozen soil was analyzed. Overall, applying IPSS to the soil was an effective and feasible measure for reinforcing a warm frozen soil foundation.

Design of a variable valve hydraulic lift system for diesel engine

Zhilong Hu,Yong Gui,Min Xu,Kangyao Deng,Yi Cui,Jiayong Dou 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

A continuous variable valve lift (VVL) mechanism for a diesel engine is proposed in this research. The hydraulic mechanism, whichconsists of a driving plunger, a driven plunger, a hydraulic cylinder, and a hydraulic oil tank, is the key part of the VVL mechanism. Simulation is conducted to study the relationship between maximum valve lift and rotation angle of driving plunger. Calculation resultsindicate that the maximum valve lift decreases with increasing rotation angle. A prototype was manufactured and successfully tested in asingle-cylinder diesel engine. The experiments, which were conducted at different rotation angles of the driving plunger, validate theaccuracy of the calculation results. The difference between experimental valve lift curve and cam lift curve is considered the result of oilleakage. Rotating the driving plunger is an effective method to regulate valve lift. Working stability of the VVL mechanism is validatedthrough a multi-cycle operation. Experimental results indicate that the VVL mechanism is effective and reliable for realizing continuousVVL in engines.

Sliding model synchronous control based on RBFN of multiple exciters in vibration system

Zhilong Huang,Lei Shan,Jintao Lai,Jinzhong Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.10

To analyze the synchronization control problems of multiple homodromy exciters in nonlinear vibration system of machinery-material (NVS-MM), nonlinear vibration system dynamics model under excitation of multiple exciters considering the nonlinear support and influence of the material is derived. Aiming at the synchronous control problem of NVSMM, a controller based on radial basis function network global sliding mode control (RBFNGSMC) algorithm and adjacent cross-coupling control (ACCC) strategy is established. Using RBFN to adaptively approximate total uncertainty of NVS-MM can effectively reduce estimation error. Using RBFN method instead of the symbol function can suppress chattering of system and stabilized the response of the system. Performance of the proposed RBFN-GSMC algorithm is further analyzed and verified by numerical simulation. Results show that compared with other control methods, effectiveness of proposed ACCC strategy combined with RBFNGSMC algorithm is verified. ACCC strategy can improve synchronization control accuracy of multiple homodromy exciters in the NVS-MM. Finally, by studying the influence of parameter disturbances in the NVS-MM on the performance of controller, it is proved that proposed controller is robust to external loads or parameter disturbances.

Research for Classification Method of Battery Based on State of Health

Yu Zhilong,Li Ran 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.6

In order to solve the problems that lithium-ion power battery cannot reflect state of health(SOH) in sorting process , the parameters which can reflect the battery SOH, such as capacity, AC resistance and self-discharge current, were used as the input vector of battery sorting model, fuzzy c-means clustering analysis and support vector machine based on cross validation algorithm to the battery for classification and recognition were used, and lithium power battery sorting model was established and the same batch of power battery were separating tested and according to the experimental results, batteries was divided into groups. The test results showed that: battery electrochemistry was having a good consistency. The variation of capacitance was less than 5% while there was 1500 cycle life.

Seeing the Unseen Menu

Jin, Zhilong(김지룡),Han, Eunkyoung(한은경) 한국광고홍보학회 2016 한국광고홍보학보 Vol.18 No.3

본 연구는 “고스트 아이템”의 이용 동기를 살펴보고 이에 따라 이용 동기가 행동 의도(구매 의도와 구전 의도)에 미치는 영향을 분석하였다. 또한 “고스트 아이템”의 이용 동기와 행동 의도의 관계에서 독특성 욕구의 조절 효과를 살펴보았다. 연구 방법으로는 “고스트 아이템”의 이용 동기를 알아보기 위해 델파이 기법을 사용하고 요인 분석을 실시하였다. 또한 이용 동기가 행동 의도에 미치는 영향과 독특성 욕구의 조절 효과를 분석하기 위해 조절 회귀분석을 사용하였다. 연구 결과, “고스트 아이템”의 이용 동기는 “차별성 추구”, “자기 만족 추구”, “호기심 추구”와 “혁신성 추구” 4가지 요인으로 도출되었다. “고스트 아이템”의 이용 동기는 모두 행동 의도에 긍정적인 영향을 미치는 것으로 나타났다. 독특성 욕구는 “고스트 아이템”의 이용 동기와 행동 의도의 관계에 있어 유의미한 조절 효과가 나타났다. 연구 결과를 바탕으로 이론적 함의와 실무적 함의가 논의되었다. The main purpose of this study was to provide the motivation for consumers to use “ghost items” and to analyze the impact of these motivation on behavioral intentions (purchase and word of mouth). In addition, as a propensity, need for uniqueness was used to reflect consumers’ perceptions of their difference to others. Accordingly, the moderating effect of need for uniqueness between motivation and behavioral intention was also examined. The result of this research indicated that “will to differentiation”, “will to self-satisfaction”, “will to curiosity” and “will to innovativeness” were motivation of consumers to use “ghost items”. These motivation to use “ghost items” had positive effect on behavioral intention. Need for uniqueness moderated the relationship between motivation and behavioral intention significantly. A number of implications on consumers motivation and the effects of need for uniqueness on behavioral intention are discussed.

방사선 노출 예방 행위 의도와 방사선량 측정 애플리케이션의 수용 의도

김지룡(Jin, Zhilong),한은경(Han, EunKyoung) 한국광고홍보학회 2017 한국광고홍보학보 Vol.19 No.1

본 연구는 병행과정확장모델(EPPM)과 기술수용모델(TAM)을 바탕으로 일반 국민들이 방사선 노출에 대하여 지각하는 위협(심각성, 취약성)과 방사선량 측정 애플리케이션에 대한 효능감(반응 효능감, 자기 효능감)이 예방 태도와 예방 행위 의도에 미치는 영향을 살펴보았다. 또한 위험 통제, 공포 통제, 무반응 세 가지 위협 처리 과정에 따라 스마트폰 방사선량 측정 애플리케이션에 대한 용이성과 유용성의 지각 차이를 알아보고 지각된 용이성, 유용성과 방사선량 측정 애플리케이션의 수용 의도 간 프라이버시 염려의 조절 효과를 분석하였다. 연구 방법으로는 온라인 설문 조사(연구1: N = 372명; 연구2:N = 330명)를 진행하였다. 연구 결과 심각성, 반응 효능감, 자기 효능감은 예방 태도에 긍정적인 영향을 미쳤다. 또한 방사선량 측정 애플리케이션에 대한 용이성과 유용성에 있어서 위협과 효능감에 따라 세 그룹 간에 유의미한 차이가 있는 것으로 나타났다. 마지막으로 프라이버시 염려의 조절 효과는 지각된 용이성과 방사선량 측정 애플리케이션 수용 의도의 관계에서만 나타났다. 지각된 유용성과 방사선량 측정 애플리케이션 수용 의도 간 프라이버시 염려의 조절 효과는 나타나지 않았다. The purposes of this study are to investigate the effects of perceived threat(severity of threat and susceptibility to threat) and perceived efficacy(self-efficacy and response efficacy) on preventive attitude and preventive behavior intention from radiographic exposure. In order to compare the level of perceived ease of use and usefulness of dosimetry application by three kinds of threat processing groups(danger control, fear control and no response). To investigate moderating effects of privacy concern on the relationship between perceived ease of use, usefulness and acceptance intention of dosimetry application. This article was conducted with experimental study(Study 1: N=372; Study 2: N=330) and online survey. Results of Study 1 indicate that severity of threat, response efficacy and self-efficacy have a positive effect on the attitude toward prevention, and preventive behavior intention changes depending on the attitude toward prevention. Results of Study 2 indicated that danger control group perceived ease of use and usefulness of dosimetry application better than others. Privacy concern only influenced the relationship between perceived ease of use and acceptance intention of dosimetry application.

화장품기업의 평판과 투하자본수익률에 관한 연구

김지룡(Jin Zhilong),한은경(Han Eunkyoung) 한국HCI학회 2019 한국HCI학회 학술대회 Vol.2019 No.2

화장품 제품의 균질화로 인해 제품의 차별화를 통한 경쟁은 더 이상 의미가 없게 되었다. 따라서 기업 간 경쟁에 있어 기업평판이 주목을 받게 되었다. 긍정적인 기업평판은 기업의 경쟁우위를 유지하고 가치를 창출의 토대가 된다. 그러나 기업평판의 형성에 있어 미디어의 영향을 간과할 수 없다. 따라서 본 연구에서는 온라인 뉴스와 뉴스댓글로 형성된 기업평판과 기업수익성 간 의 관계를 알아보았다. 연구방법은 빅데이터 분석을 실시하였다. 본 연구에서는 화장품 기업인 아모레퍼시픽을 대상으로 실제 온라인 뉴스와 뉴스댓글 데이터를 수집하였으며 비정형데이터 분석을 위해 텍스트마이닝을 실시하였다. 연구 결과 온라인 뉴스와 뉴스댓글로 형성된 기업평판 모두 기업의 수익성에 유의미한 영향을 미치는 것으로 나타났다. 그 중에서 온라인 뉴스보다 뉴스 댓글로 형성된 기업평판이 더 큰 영향력을 미치는 것으로 나타났다. 본 연구를 통해 온라인 뉴스와 뉴스댓글의 중요성을 부각하고 기업평판과 수익성 간의 관계를 알아봄으로써 향후 효율적인 평판관리전략을 수립하는데 기여하고자 한다.

Analysis of Rock Mass Parameters and Plastic Zone of a Tunnel in Southwest Mountainous Area

Mengni Wang,Zhilong Zhang,Li Ren,Ru Zhang,Liangjuan Zheng,Lanbin Zhang,Zetian Zhang,Jing Xie,Xiaoling Liu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.12

The deformation damage and support difficulties caused by the formation and expansion of plastic zone of surrounding rock have always been urgent engineering problems to be solved, especially in areas with prominent non-uniform stress fields. Choosing a reasonable and practical method to determine the plastic zone is of great significance for ensuring the long-term stability and safety of tunnels. Based on a tunnel project in the southwest mountainous area, this paper conducted mechanical tests to obtain the mechanical parameters of granite. The analytical method optimized based on the principle of stress balance was applied, and the numerical simulation was carried out according to the field displacement monitoring data and experimental parameters, the plastic zone of the medium quality granite cross-section and fault fracture zone granite cross-section was analyzed comprehensively. The results shown that the analytical and numerical solutions are in good agreement with engineering practice. It proved that the theory and method in this paper are scientific and practical in engineering. The research results can provide support for the design optimization and construction safety of the tunnel, and the research ideas and methods can also provide reference for similar projects.