scholarly journals Experimental Evaluation of Fragments from TBM Disc Cutting under Different Load Cases

2018 ◽  
Author(s):  
Yimin Xia ◽  
Yupeng Shi ◽  
Laikuang Lin ◽  
Yichao Zhang ◽  
Qing Tan ◽  
...  
Keyword(s):  
Production Rate ◽  
Specific Energy ◽  
High Efficiency ◽  
Impact Load ◽  
Tunnel Boring Machine ◽  
Cutting Parameters ◽  
Disc Cutter ◽  
Absolute Size ◽  
Coarseness Index ◽  
Construction Efficiency

The Tunnel Boring Machine (TBM) tunneling process always contains a certain degree of vibrations due to the step broken phenomenon of the cutting tools. Undoubtedly, there is a quite difference in the fragment characteristics which are related to the construction efficiency of TBM under the static load and the combination of static and impact load. In this study, a series of rock breaking tests with a 216 mm diameter disc cutter and marble samples were conducted under different load cases. Based on the Rosin–Rammler distribution curve, the fragments from the cutting tests were also sieved to calculate the absolute size constant (x’) and coarseness index (CI). The relationship between coarseness index, absolute size parameter and the cutting parameters, specific energy, production rate was evaluated. The results show that there is an increasing trend of x’ and CI with the increase of cut spacing and penetration as well as adding impact load component. An overall downtrend in specific energy and upward trend in production rate which are associated with the high efficiency can be observed with the increasing CI and x’. It is believed that the conclusions are of great significance for improving TBM construction efficiency and cutterhead design.

scholarly journals Acoustic Emission Characteristics During Rock Fragmentation Processes Induced by Disc Cutter under Different Water Content Conditions

2019 ◽  
Vol 9 (1) ◽  
pp. 194 ◽  
Author(s):  
Qibin Lin ◽  
Ping Cao ◽  
Rihong Cao ◽  
Xiang Fan
Keyword(s):  
Acoustic Emission ◽  
Water Content ◽  
Specific Energy ◽  
Tunnel Boring Machine ◽  
Rock Breaking ◽  
Rock Fragmentation ◽  
Disc Cutter ◽  
Physical Acoustics ◽  
Indentation Force ◽  
Penetration Force

Based on a properly modified testing platform and Physical Acoustics Corporation (PAC) Micro-II acoustic emission (AE) system, a series of sequential indentation tests on granite samples with five different water contents was conducted to investigate the effect of the water content on the rock fragmentation process induced by a tunnel boring machine (TBM) disc cutter. During these tests, the effects of the water content on the characteristics of the peak penetration force, AE events, consumed energy, rock chip volume, and specific energy were analyzed. The results showed that the AE events were associated with the whole second indentation process of the granite. Under conditions with the same water content, the peak penetration forces and the consumed energy were smaller than those in the first indentation force. Additionally, subsequent chips were formed more frequently than the first indentation chips. The specific energy was lower, which meant that the rock breaking efficiency was higher. With the increase in the water content, the acoustic emission events reduced. The peak penetration force and consumed energy decreased with the increase in the water content. The volume of the chips increased significantly as the water content increased. The specific energy was promoted by the increase of the water content and then by the increase in the rock-breaking efficiency of the TBM disc cutter.

A Method to Predict Disc Cutter Specific Energy for TBM Based on CSM Model

2012 ◽  
Vol 236-237 ◽  
pp. 414-417
Author(s):  
Gang Li ◽  
Li Da Zhu ◽  
Jian Yu Yang ◽  
Wan Shan Wang
Keyword(s):  
Specific Energy ◽  
Performance Prediction ◽  
Dynamic Models ◽  
Tunnel Boring Machine ◽  
Disc Cutter ◽  
Energy Prediction ◽  
Tunnel Boring ◽  
Csm Model ◽  
Tbm Cutter ◽  
Cutter Head

By using fracture mechanics theory of rock, the rock fragmentation mechanism of tunnel boring machine (TBM) cutters is analyzed and the analysis of forces of cutter is carried out. A new method to predict disc cutter specific energy for TBM is developed in this study. By using the dynamic models of TBM cutters interaction with the rock, specific energy prediction model for TBM cutter head is developed. The data from the actual tunnel construction is analyzed by using an example of Qinling tunnel and the comparison is made with the field data. The results indicate that the model developed in this study could not only replace the experiment to disc cutter specific energy for TBM, but also provide a theoretical basis for the performance prediction and optimal design of cutter head for TBM.

The Development of the TBM Disc Cutter Test Device for Cutting Rock

2014 ◽  
Vol 889-890 ◽  
pp. 292-296 ◽  
Author(s):  
Yi Min Xia ◽  
Tao Ouyang ◽  
Lv Jian Xie ◽  
Qing Tan ◽  
Chun Lei Luo ◽  
...  
Keyword(s):  
High Efficiency ◽  
Static Load ◽  
Impact Load ◽  
Indentation Test ◽  
Wear Test ◽  
Disc Cutter ◽  
Test Machine ◽  
Test Device ◽  
Vertical Loading ◽  
Cutting Test

In order to study the disc cutter cutting performance and the cutters combination feature and to explore a new high-efficiency breaking method in hard rock environment, a new multifunction disc cutter test device plan is established and carried out based on the analysis of relevant research and test equipment at home and abroad. The test device consists of a vertical loading mechanism, a longitudinal cutting mechanism, a shock loading mechanism and a control system, etc. It can be used to conduct not only single test such as cutting under static load, fragmentation under impact load, indentation test under static load and wear test of the disc cutter, but also combined cutting test under impact and static load. At last, granite was cut on this test device by the TBM disc cutter under different loads, the results are desirable and show that the test machine can provide the relevant test conditions and the basic data for the design of the TBM disc cutter.

scholarly journals Study on Cutting Chip in Milling GH4169 with Indexable Disc Cutter

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3135
Author(s):  
Gensheng Li ◽  
Chao Xian ◽  
Hongmin Xin
Keyword(s):  
Chip Thickness ◽  
Cutting Parameters ◽  
Disc Cutter ◽  
Maximum Deviation ◽  
Feed Speed ◽  
Deviation Rate ◽  
Qualitative Relationship ◽  
Predicted Values ◽  
Deformation Coefficient ◽  
And Control

The study and control for chip have a significant impact on machining quality and productivity. In this paper, GH4169 was cut with an indexable disc milling cutter. The chips corresponding to each group of cutting parameters were collected, and the chip parameters (chip curl radius, chip thickness deformation coefficient, and chip width deformation coefficient) were measured. The qualitative relationship between the chip parameters and cutting parameters was studied. The quadratic polynomial models between chip parameters and cutting parameters were established and verified. The results showed that the chip parameters (chip curl radius, chip thickness deformation coefficient and chip width deformation coefficient) were negatively correlated with spindle speed; chip parameters were positively correlated with feed speed; chip parameters were positively correlated with cutting depth. The maximum deviation rate between measured values and predicted values for chip curl radius was 9.37%; the maximum deviation rate for cutting thickness deformation coefficient was 13.8%, and the maximum deviation rate of cutting width deformation coefficient was 7.86%. It can be seen that the established models are accurate. The models have guiding significance for chip control.

scholarly journals Measurement of Ozone Production Sensor

2010 ◽  
Vol 3 (3) ◽  
pp. 545-555 ◽  
Author(s):  
M. Cazorla ◽  
W. H. Brune
Keyword(s):  
Production Rate ◽  
High Efficiency ◽  
Ambient Air ◽  
Ozone Production ◽  
State University ◽  
Photostationary State ◽  
Sample Chamber ◽  
Efficiency Conversion ◽  
The Difference ◽  
Teflon Film

Abstract. A new ambient air monitor, the Measurement of Ozone Production Sensor (MOPS), measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, flowing ambient air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The air flows that exit the two chambers are sampled by an ozone monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.

Research and Application on High Efficiency Reversible Cutting Technique

2004 ◽  
Vol 471-472 ◽  
pp. 825-829
Author(s):  
Wen Ge Wu ◽  
Si Qin Pang ◽  
Qi Xun Yu
Keyword(s):  
High Efficiency ◽  
Cutting Tool ◽  
Handling Time ◽  
Cutting Parameters ◽  
Machining Process ◽  
Processing Route ◽  
Rough Machining ◽  
Machined Surface ◽  
Primary Motion ◽  
The Way

Reversible cutting method is a research thesis proposed to shorten processing route, decrease tool number and handling time, increase machining efficiency. There are three movement ways, i.e. reversible feed motion, reversible primary motion and reversible composite motion. Primary motion is done by workpiece, conventional or reversible feed motion is done by cutting tool in the way of reversible feed motion, e.g. turning. Cutting velocity is passed to cutting tool, clockwise or anti-clockwise cutting movement is done by cutting tool in the way of reversible primary motion, e.g. milling, shaping, drilling (spade drill), reaming. Primary and feed motions are all reversible in composite motion, e.g. turn-milling. Chip deformation and machined surface with reversible finishing is discussed. A mechanical analysis is carried out to the workpiece deformation of slender shaft turning in normal direction and reversible direction. The result has been verified by experiments. Experimental data for the range of cutting parameters tested showed that the reversible fine machining produce the compressive residual stresses at the surface, which are critical in the performance of the machined components. Experimental research indicted that the results of micro-hardness of reversible fine machining technique are smaller than that of general fine machining show that decreased plastic deformation of the surface layer and work-hardening. It can be adopted such planning which rough machining during advance stroke and fine machining during return stroke in machining process.

scholarly journals Tunnel boring machine cutterhead crack propagation life prediction with time integration method

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985345 ◽  
Author(s):  
Jianbin Li ◽  
Zhange Zhang ◽  
Zhichao Meng ◽  
Junzhou Huo ◽  
Zhaohui Xu ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Prediction Model ◽  
Crack Growth ◽  
Life Prediction ◽  
Impact Load ◽  
Time Integration ◽  
Tunnel Boring Machine ◽  
Propagation Model ◽  
Strong Impact ◽  
Tunnel Boring

Fatigue damage is one of the most common failure modes of large-scale engineering equipment, especially the full-face tunnel boring machine with characteristics of a thick plate structure bearing strong impact load. It is difficult to predict the location and propagation life of crack of cutterhead under strong impact load. Unseasonal maintenance of equipment caused by inaccurate prediction of life cycle of cutterhead seriously affects the construction efficiency of the equipment and the life safety of the operators. Determining the crack location of tunnel boring machine cutterhead structure under strong impact load and predicting the crack propagation life are difficult scientific problems. To solve them, first, the location of the stress concentration of the cutterhead is determined by using finite element analysis method of statics. Second, prediction model for crack propagation life of tunnel boring machine cutterhead characteristic substructure based on time integration is built. And the test of crack growth of cutterhead characteristic substructure is performed. The feasibility and accuracy of the prediction model are verified by contrasting crack prediction models and the results of the test. Finally, the life prediction of tunnel boring machine cutterhead of water diversion project in Northwest Liaoning Province is carried out by using crack propagation model based on time integration. Results show that the maximum error of theoretical prediction and experimental results of crack propagation is 16%. So the feasibility of crack propagation model based on time integration in predicting the crack growth of cutterhead is verified. It is predicted that the tunnel boring machine cutterhead panel can work normally for 5.9 km under the condition of ultimate load. Building the crack propagation model considering the influence of plate thickness and strong impact load has important research value for improving the working efficiency of engineering equipment, prolonging service time, and improving the working safety.

Prediction models for specific energy consumption of machine tools and surface roughness based on cutting parameters and tool wear

2020 ◽  
pp. 095440542097106
Author(s):  
Yu Su ◽  
Congbo Li ◽  
Guoyong Zhao ◽  
Chunxiao Li ◽  
Guangxi Zhao
Keyword(s):  
Surface Roughness ◽  
Energy Consumption ◽  
Tool Wear ◽  
Specific Energy ◽  
Machine Tools ◽  
Prediction Models ◽  
Specific Energy Consumption ◽  
Cutting Parameters ◽  
Experimental Results ◽  
Support Vector

The specific energy consumption of machine tools and surface roughness are important indicators for evaluating energy consumption and surface quality in processing. Accurate prediction of them is the basis for realizing processing optimization. Although tool wear is inevitable, the effect of tool wear was seldom considered in the previous prediction models for specific energy consumption of machine tools and surface roughness. In this paper, the prediction models for specific energy consumption of machine tools and surface roughness considering tool wear evolution were developed. The cutting depth, feed rate, spindle speed, and tool flank wear were featured as input variables, and the orthogonal experimental results were used as training points to establish the prediction models based on support vector regression (SVR) algorithm. The proposed models were verified with wet turning AISI 1045 steel experiments. The experimental results indicated that the improved models based on cutting parameters and tool wear have higher prediction accuracy than the prediction models only considering cutting parameters. As such, the proposed models can be significant supplements to the existing specific energy consumption of machine tools and surface roughness modeling, and may provide useful guides on the formulation of cutting parameters.

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