Calculating the attenuation of stress waves passing through an in situ stressed joint using a double nonlinear model

2021 ◽  
pp. 1-21
Author(s):  
Tingting Liu ◽  
Luyang Ding ◽  
Yun Zheng ◽  
Xinping Li ◽  
Chuangchuang Li
Keyword(s):  
Nonlinear Model ◽  
Stress Waves ◽  
Double Nonlinear

scholarly journals Road Pavement Stiffness Determination using SASW Method

2012 ◽  
Vol 3 ◽  
pp. 9-16 ◽  
Author(s):  
M. A. Ismail ◽  
A. R. Samsudin ◽  
A. G. Rafek ◽  
K. A. M. Nayan
Keyword(s):  
Rayleigh Wave ◽  
Wave Motion ◽  
Stress Waves ◽  
Velocity Versus ◽  
Road Pavement ◽  
Iterative Inversion ◽  
Shear Wave Velocity Profile ◽  
Pavement Construction

 The Spectral Analysis of Surface Waves (SASW) method is an in-situ seismic technique for the evaluation and assessment of road pavement. The method is based on the theory of stress waves propagating in elastic media with the key elements being the generation and detection of Rayleigh wave motion. A set of transient impact source with a range of frequencies is used to generate the Rayleigh wave energy that is able to propagate along the surface layer of the pavement. Through two vertical accelerometers, the motion of the wave for each range of frequency is recorded and calculated using a dynamic signal analyzer. A dispersion curve is then constructed from the cross-power spectrum of the Fast Fourier Transform (FFT) that results in the phase velocity versus wavelength plot. An iterative inversion is then carried out to obtain the shear wave velocity profile with depth and the corresponding dynamic modulus of each pavement units. This paper presents a case study carried out on a new road pavement construction site. It was found that the profile of the dynamic shear and Young’s modulus versus depth obtained from SASW method

Analysis of Seismic Waves Propagating through an In Situ Stressed Rock Mass Using a Nonlinear Model

2020 ◽  
Vol 20 (3) ◽  
pp. 04020002
Author(s):  
Tingting Liu ◽  
Xinping Li ◽  
Yun Zheng ◽  
Fei Meng ◽  
Dongri Song
Keyword(s):  
Rock Mass ◽  
Nonlinear Model ◽  
Seismic Waves

Understanding of the Scattering of Incident Stress Waves by Defects on the Blind Side of Fuel Vent Hole

2013 ◽  
Vol 558 ◽  
pp. 400-410
Author(s):  
Cain Doherty ◽  
Wing Kong Chiu
Keyword(s):  
Composite Structures ◽  
Analytical Approach ◽  
Scattered Wave ◽  
Stress Waves ◽  
Computational Studies ◽  
Blind Side ◽  
Plate Waves ◽  
Accessible Surface ◽  
Incident Waves

This paper reports on findings that extend previous work for the purpose of in-situ structural health monitoring of defects on the blind side of open holes using plate waves. A series of computational studies is presented to understand how and why the ultrasonic scattered wave field can be detected on the accessible surface. The uniqueness of these findings is that the length-scale of the defect and the incident waves are comparable. The combination of the experimental-computational-analytical approach gives rise to new insights and guidance for the quantification of defects located in hard-to-inspect regions of future unitised metallic and composite structures. The outcomes advance the knowledge base of inspection of hard-to-access regions with actuators and sensors placed in easily accessible locations.

scholarly journals A Feasibility Study on Monitoring Pile-Soil Bonding Condition Using Piezoceramic Transducer and Horizontal Impact

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Daopei Zhu ◽  
Siyuan Tian ◽  
Haocheng Yan ◽  
Zhangli Wang
Keyword(s):  
Health Monitoring ◽  
Piezoelectric Ceramic ◽  
Safety Assessment ◽  
Stress Waves ◽  
Time Varying ◽  
Induced Stress ◽  
Bonding Condition ◽  
Smart Aggregate

The in situ evaluation of pile-soil bonding condition plays an important role for pile safety assessment in its life cycle. However, so far, there is still no fully mature tool to analyze such couplings, since the pile-soil coupling exhibits complex and time-varying relationships. This paper innovatively proposes a health monitoring approach to evaluate the bonding status of the soil and pile contact area. An impact method based on a piezoelectric ceramic sensor is proposed to monitor the bond of pile and soil. A horizontal impact was introduced near the top of the pile, and the induced stress waves were detected by the piezoceramic smart aggregate (SA) sensor embedded in the pile. Different crack damage sizes were made between the soil and the pile to investigate the change of the bonding. An energy index was developed to quantitatively evaluate the quality of the bonding as a pile-soil bonding index. The proposed approach inspired a potential way to directly judge if there is crack damage between the pile and soil and to evaluate pile safety.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

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