Improved SVR Method for Predicting the Cutting Force of a TBM Cutter Using Linear Cutting Machine Test Data

Author(s):  
Mengmeng Hu ◽  
Biao Li ◽  
Bo Zhang ◽  
Ruirui Wang ◽  
Lei Chen
2012 ◽  
Vol 476-478 ◽  
pp. 1718-1721 ◽  
Author(s):  
De Hong Jiang ◽  
Li Ming Bian

The attrition rate of a TBM cutter connects with the economic benefits of the TBM application and digging efficiency. The main influence factor of the attrition rate of the TBM cutter is rock abrastivity. The rock abrastivity is in contact with the physical and mechanical indexes of rock and rock attributes. The relationship between the rock abrastivity and the physical and mechanical indexes of rock is studied by experiments and mathematical statistics. The experimental samples are collected in the Qingdao subway tunnel and done rock mechanics room experimentation and rock abrastivity experimentation separately in the lab Based on calculation and analyses of the test data. We obtain a mathematic model describing the relationship between rock abrastivity and physical and mechanical indexes of rock and summarize and interpret the correlativity between them.


Tribologia ◽  
2019 ◽  
Vol 288 (6) ◽  
pp. 81-85
Author(s):  
Jacek Przepiórka

Cutting natural leather is a first stage of a technological process of leather goods. It consists of dividing flat materials into shoe components. Cutting can be done by hand or mechanically. Cutters are the main cutting device in mechanical process. During utilization of cutters, the durability of its usage is an important issue. To increase its endurance, optimal force conditions are required. These depend on the following: the friction coefficient between cutting machine and cut material, the angle of sharpening of cutter, the blunting of the edge, using a cutting pad, and the type and kind of steel of which is produced. Friction is a component of a cutting force and its value depends on several factors, one of which is shape of the cutter. It is a parameter often ignored in the literature; however, according to the studies conducted by the authors, the value of the friction during cutting depends on the shape of the cutter. In this study, results of force value measurements required to cut elements of different shapes with equal circumferences with steel cutters are presented.


Author(s):  
Xuhui Zhang ◽  
Jianmin Li ◽  
Yimin Xia ◽  
Laikuang Lin ◽  
Mi Li ◽  
...  

The pre-cutting machine is becoming valued due to its ability to effectively prevent surface settlement and reduce vibration in tunnel construction. To obtain the cutting characteristics and layout of pre-cutting machine cutter, the cutting tests by the pre-cutting machine cutter are conducted and the cutting laws are also studied. The research results show that the cutting force rather than normal force and side force is responsible for the rock breaking. With the increase of the cutting depth and cutting spacing, the cutting forces increase generally. But for the little value of cutting spacing, the cutting force can not increase continuously when the cutting depth increase to a relatively large value. Furthermore, for a given cutting depth, the cutting force will keep at an approximate constant rather than continuous increase with the increase of the cutting spacing when the cutting spacing increases to a relatively large value. The specific energy decreases nonlinearly with the increase of cutting depth and the decrease of specific energy is not significant when the cutting depth is more than 12 mm. Moreover, there exists an optimal cutting spacing for a given cutting depth. To maintain a desirable cutting efficiency, the ratio of cutting spacing to cutting depth should be controlled between 1 and 2. Finally, the layout plan of the pre-cutting machine cutter is proposed based on the research results and is applied in the actual manufacturing of the pre-cutting machine.


2016 ◽  
Vol 32 (3) ◽  
pp. 204-214 ◽  
Author(s):  
Emilie Lacot ◽  
Mohammad H. Afzali ◽  
Stéphane Vautier

Abstract. Test validation based on usual statistical analyses is paradoxical, as, from a falsificationist perspective, they do not test that test data are ordinal measurements, and, from the ethical perspective, they do not justify the use of test scores. This paper (i) proposes some basic definitions, where measurement is a special case of scientific explanation; starting from the examples of memory accuracy and suicidality as scored by two widely used clinical tests/questionnaires. Moreover, it shows (ii) how to elicit the logic of the observable test events underlying the test scores, and (iii) how the measurability of the target theoretical quantities – memory accuracy and suicidality – can and should be tested at the respondent scale as opposed to the scale of aggregates of respondents. (iv) Criterion-related validity is revisited to stress that invoking the explanative power of test data should draw attention on counterexamples instead of statistical summarization. (v) Finally, it is argued that the justification of the use of test scores in specific settings should be part of the test validation task, because, as tests specialists, psychologists are responsible for proposing their tests for social uses.


Sign in / Sign up

Export Citation Format

Share Document