Research on the detection system for impact energy of pneumatic drill based on stress wave technique

2015 ◽  
Author(s):  
Zheng Sulu ◽  
Wang Dongdong ◽  
Zheng Ruihang ◽  
Wang Xiangping ◽  
Mao Yunyan
Keyword(s):  
Stress Wave ◽  
Impact Energy ◽  
Detection System ◽  
Pneumatic Drill ◽  
Wave Technique

Study on Application of Stress Wave for Nondestructive Test of Wood Defects

2013 ◽  
Vol 401-403 ◽  
pp. 1119-1123 ◽  
Author(s):  
Wen Shu Lin ◽  
Jin Zhuo Wu
Keyword(s):  
Nondestructive Test ◽  
Stress Wave ◽  
Significant Influence ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Wood Products ◽  
Propagation Time ◽  
Propagation Parameters ◽  
Wave Technique ◽  
Wooden Structures

The elm wood samples were tested by the technique of stress wave, and the testing results were analyzed by using the statistic software of SPSS. The results showed that the moister content of wood, wood crack, the sizes of holes and numbers of holes have significant influence on propagation parameters and dynamic modulus of elasticity. Under the same specifications, the propagation time of the stress wave was longer in the wood with holes or cracks than the perfect wood samples, and the time become longer with the increasing the sizes and numbers of holes or cracks. The studying results of the thesis will provide a sound background for the application of stress-wave technique in detecting the inner defects of wood products and other wooden structures.

Impact compression behaviors of high-capacity long piles

2010 ◽  
Vol 47 (12) ◽  
pp. 1335-1350 ◽  
Author(s):  
Arthur K.O. So ◽  
Charles W.W. Ng
Keyword(s):  
Energy Transfer ◽  
Impact Velocity ◽  
Stress Wave ◽  
Impact Energy ◽  
High Capacity ◽  
Measured Data ◽  
Impact Compression ◽  
Impact Forces ◽  
The Impact ◽  
Pile Length

The Hiley formula underestimates driving resistance of long piles. Methods using affected pile length have been suggested, but have been found to be inapplicable for high-capacity piles. The impact compression behaviors of about 4700 high-capacity H-piles that were 14–80 m long at final set were studied. Measured data revealed that maximum impact forces are very scattered, but their means are independent of the hammer type, ram weight, ram drop, impact velocity, and pile length. Maximum impact compression of pile and affected pile length exist in both long and short piles. The affected pile length in turn is significant to the blow efficiency, hammer constant, and energy transfer ratio. This length is governed by the impact momentum and impact energy, and can be estimated by an energy-based equation. If the affected pile length determined by this equation is substituted into the Hiley formula to back-analyze the driving resistance, predictability of the driving formula can be improved by about 8%. This improvement is significant enough to reduce the number of hammer blows required at very hard driving conditions and reduce pile damage. Furthermore, this proposed equation is simple to use in the field and is more economical compared with stress-wave monitoring techniques.

scholarly journals Eye Blink Detection System for Paralyzed Patients

2020 ◽  
Vol 8 (6) ◽  
pp. 333-336
Keyword(s):  
Motor Neurons ◽  
Detection System ◽  
Brain Wave ◽  
Eye Blink ◽  
Video Oculography ◽  
Incurable Disease ◽  
Blink Detection ◽  
Wave Technique ◽  
Paralyzed Patient ◽  
Visual Technologies

Paralysis of an human being is caused due to the degeneration of motor neurons which weakens the muscle, so that it does not allow patient to move, speak, breathe , and loss in the voluntary actions. It is an incurable disease. To understand the feelings of a paralyzed patients Brain wave technique and Electro-oculography techniques were used. These techniques are afflictive, discomfortable and leads to unconsciousness of the paralyzed patient. The real time video oculography system fills the communication gap between the patient and the world. Video Oculography (VOG) is video-based method of measuring the vertical, torsional and horizontal position components of both the eye blinks with the help of small cameras placed in the head-mounted mask .This paper presents different visual technologies, such as eye blink detection, eye center localization and conversion of the eye blink to speech. The video oculography could achieve accuracy of 0.968.

scholarly journals Investigation of wooden sheet pile wall in an aggressive environment using non-destructive methods

2018 ◽  
Vol 251 ◽  
pp. 02038 ◽  
Author(s):  
Marek Wyjadłowski ◽  
Tomasz Nowak ◽  
Anna Karolak
Keyword(s):  
Ultrasonic Wave ◽  
Stress Wave ◽  
Sea Water ◽  
Water Environment ◽  
Sheet Pile ◽  
Strength Parameters ◽  
Comprehensive Information ◽  
Wave Technique ◽  
Non Destructive ◽  
Variable Water

The paper presents the study of the strength parameters of wood samples from the retaining structure, working for about 60 years in an aggressive sea water environment. Samples from the variable water level zone and situated in the watered ground were tested. Non-destructive examinations were performed using the following methods: the stress wave technique and the ultrasonic wave technique. The results presented below can lead to the conclusion that both methods: the stress wave by Fakopp Microsecond Timer device and the ultrasonic wave by Sylvatest Trio correspond with each other and result in similar outcomes. However, in order to obtain more detailed and comprehensive information on the elements properties, more research should be conducted.

Study on Oil Pipeline Leakage Detection Based on Stress Wave Detection Technique and Wavelet Analysis

2013 ◽  
Vol 694-697 ◽  
pp. 1368-1371
Author(s):  
Jie Zhang ◽  
Xiao Dan Guan ◽  
Yan Sun ◽  
Xue Jie Wei
Keyword(s):  
Wavelet Analysis ◽  
Stress Wave ◽  
Detection System ◽  
Vibration Signal ◽  
Detection Technique ◽  
Vibration Sensor ◽  
Processing Unit ◽  
Leakage Detection ◽  
Oil Pipeline ◽  
Wave Detection

Based on stress wave detection technique and wavelet analysis, oil pipeline leakage detection system is designed. Through vibration sensor put on the pipeline, vibration signal of pipeline is collected. The signal is used to preliminary assessment with DSP processing unit within the system, and then the feature of threat events is extracted. The information is uploaded to the centre of security central station of system by GPRS signal. At this, signal wavelet analysis is done for leakage detection. Based on LabVIEW platform, on oil pipeline leakage monitoring interface, threat events is alarmed and shown in electronic map and the system is convenient for staff to handle with. With the test, recognized police rate of system is superior to 85%, rate of false alarm is 15% below. All knocking signal of pipeline is given right alarm information. The noise by people walk, car, wind and rain is effectively filtered.

Application Progress of Nondestructive Testing Technique of Hydraulic Concrete Based on Steady Rayleigh Wave Method

2014 ◽  
Vol 608-609 ◽  
pp. 775-781
Author(s):  
Zhong Jun Deng ◽  
Cheng Lin Yao ◽  
Yong Mei Jia ◽  
Yu Bo Yang ◽  
Gui Bin Zhang
Keyword(s):  
Nondestructive Testing ◽  
Rayleigh Wave ◽  
Detection System ◽  
Crack Depth ◽  
Quantitative Detection ◽  
Characteristic Parameters ◽  
Testing Technique ◽  
Hydraulic Concrete ◽  
Wave Technique

In the large hydraulic concrete structure that conventional nondestructive testing technique can’t implement quantitative detection, using steady Rayleigh wave technique can acquire various characteristic parameters of concrete. The paper introduces the principle and detection system of steady Rayleigh wave technique systematically, and makes detection experiments to introduce steady Rayleigh wave e technique and application progress of it in quality of large hydraulic concrete and nondestructive detection of crack depth. The practice proves that steady Rayleigh wave detection technique has the characteristics of strong antijamming capability and higher detection precision.

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