scholarly journals Nondestructive Testing of Stabilized Soils and Soft Rocks via Needle Penetration

Author(s):  
Nihat Dipova

Assessing the strength of hard soils and soft rocks is a pressing issue in geotechnical investigations, since high quality core samples recommended by testing standards for strength determinations cannot always be achieved. As a solution, a light-weight, non-destructive testing device, Needle Penetrometer (NP), was developed in Japan. It is not well known and standardized in other parts of the world. No sample preparation is required, and it is applicable both in the field and laboratory with minimum surface conditioning. This study aims to provide some new contributions to previous works on the NP test, including new rock types and stabilized soils. For these purposes, unconfined strength (UCS) and needle penetration resistance (NPR) values were determined for compacted clays, lime and cement stabilized clays, micritic tufa, microdetrital tufa and pumice. A database consisting of a total of 108 UCS–NPR data pairs was established. Regression analyses reveal that, there is a significant relationship between UCS and NPR. It is concluded that the NP tests can be applied to stabilized soils and soft rocks with UCS of up to 30 MPa to predict the UCS from NPR.

2013 ◽  
Vol 64 (2) ◽  
pp. 21001 ◽  
Author(s):  
Jean-Luc Bodnar ◽  
Jean-Jacques Metayer ◽  
Kamel Mouhoubi ◽  
Vincent Detalle

2020 ◽  
pp. 54-59
Author(s):  
A. A. Yelizarov ◽  
A. A. Skuridin ◽  
E. A. Zakirova

A computer model and the results of a numerical experiment for a sensitive element on a planar mushroom-shaped metamaterial with cells of the “Maltese cross” type are presented. The proposed electrodynamic structure is shown to be applicable for nondestructive testing of geometric and electrophysical parameters of technological media, as well as searching for inhomogeneities in them. Resonant frequency shift and change of the attenuation coefficient value of the structure serve as informative parameters.


2015 ◽  
Vol 7 (2) ◽  
pp. 1428-1439
Author(s):  
Khurshed Alam ◽  
Md. Sayeedur Rahman ◽  
Md. Mostafizur Rahman ◽  
S. M. Azaharul Islam

A powerful non-destructive testing (NDT) technique is adopted to study the internal defects and elemental distribution/homogeneity and porosity of aerated brick and EPS aggregate poly brick samples. In the present study the internal defects like homogeneity, porosity, elemental distribution, EPS aggregate and aerator distributor in the test samples have been observed by the measurement of gray value/optical density of the neutron radiographic images of these samples. From this measurement it is found that the neutron intensity/optical density variation with the pixel distance of the AOI of the NR images in both expanded polystyrene (EPS) aggregate poly brick and aerated brick samples comply almost same in nature with respect to the whole AOI but individually each AOI shows different nature from one AOI to another and it confirms that the elemental distribution within a AOI is almost homogeneous. Finally it was concluded that homogeneity, elemental distribution in the EPS aggregate poly brick sample is better than that of the aerated brick sample. 


2020 ◽  
Vol 2020 (1) ◽  
pp. 34-52
Author(s):  
Rafał Szymański

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.


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