scholarly journals CRACK WIDTH MEASUREMENT FOR NON-PLANAR SURFACES BY TRIANGLE MESH ANALYSIS IN CIVIL ENGINEERING MATERIAL TESTING

2019 ◽  
Vol XLII-2/W18 ◽  
pp. 107-113 ◽  
Author(s):  
F. Liebold ◽  
H.-G. Maas ◽  
A. A. Heravi
Keyword(s):  
Crack Width ◽  
High Speed ◽  
Impact Load ◽  
Image Sequences ◽  
Stereo Image ◽  
Triangle Mesh ◽  
Engineering Material ◽  
Planar Surfaces ◽  
Width Measurement ◽  
Mesh Analysis

Abstract. This publication concentrates on the photogrammetric crack width measurement of crack patterns of concrete probes under impact loading in high-speed stereo image sequences. The presented algorithm works for non-planar specimens with deformations that only appear tangential to the surface and the method is based on triangle mesh analysis. Experiments were conducted with cylindrical specimens with an impact load affecting parallel to the main axis of the cylinder.

Measurement of Surface Changes in a Scaled-Down Landslide Model Using High-Speed Stereo Image Sequences

2016 ◽  
Vol 82 (7) ◽  
pp. 547-557 ◽  
Author(s):  
Tiantian Feng ◽  
Huan Mi ◽  
Marco Scaioni ◽  
Gang Qiao ◽  
Ping Lu ◽  
...  
Keyword(s):  
High Speed ◽  
Image Sequences ◽  
Stereo Image ◽  
Landslide Model ◽  
Surface Changes

scholarly journals Congruence analysis of point clouds from unstable stereo image sequences

2014 ◽  
Vol XL-5 ◽  
pp. 301-306 ◽  
Author(s):  
C. Jepping ◽  
F. Bethmann ◽  
T. Luhmann
Keyword(s):  
High Speed ◽  
Image Data ◽  
Point Clouds ◽  
Image Sequences ◽  
Stereo Image ◽  
Free Form ◽  
Crash Test ◽  
3D Point Clouds ◽  
Congruence Analysis ◽  
Free Form Surfaces

This paper deals with the correction of exterior orientation parameters of stereo image sequences over deformed free-form surfaces without control points. Such imaging situation can occur, for example, during photogrammetric car crash test recordings where onboard high-speed stereo cameras are used to measure 3D surfaces. As a result of such measurements 3D point clouds of deformed surfaces are generated for a complete stereo sequence. The first objective of this research focusses on the development and investigation of methods for the detection of corresponding spatial and temporal tie points within the stereo image sequences (by stereo image matching and 3D point tracking) that are robust enough for a reliable handling of occlusions and other disturbances that may occur. The second objective of this research is the analysis of object deformations in order to detect stable areas (congruence analysis). For this purpose a RANSAC-based method for congruence analysis has been developed. This process is based on the sequential transformation of randomly selected point groups from one epoch to another by using a 3D similarity transformation. The paper gives a detailed description of the congruence analysis. The approach has been tested successfully on synthetic and real image data.

scholarly journals SUB-PIXEL ACCURACY CRACK WIDTH DETERMINATION ON CONCRETE BEAMS IN LOAD TESTS BY TRIANGLE MESH GEOMETRY ANALYSIS

2018 ◽  
Vol IV-2 ◽  
pp. 193-200 ◽  
Author(s):  
F. Liebold ◽  
H.-G. Maas
Keyword(s):  
Crack Width ◽  
Concrete Beams ◽  
Geometric Analysis ◽  
Image Sequences ◽  
Reference Image ◽  
Triangle Mesh ◽  
Strain Calculation ◽  
Monocular Image ◽  
Load Tests ◽  
Geometry Analysis

This paper deals with the determination of crack widths of concrete beams during load tests from monocular image sequences. The procedure starts in a reference image of the probe with suitable surface texture under zero load, where a large number of points is defined by an interest operator. Then a triangulated irregular network is established to connect the points. Image sequences are recorded during load tests with the load increasing continuously or stepwise, or at intermittently changing load. The vertices of the triangles are tracked through the consecutive images of the sequence with sub-pixel accuracy by least squares matching. All triangles are then analyzed for changes by principal strain calculation. For each triangle showing significant strain, a crack width is computed by a thorough geometric analysis of the relative movement of the vertices.

CRACK WIDTH MEASUREMENT USING MULTISCALE LOG KERNEL

2018 ◽  
Vol 74 (2) ◽  
pp. I_30-I_39
Author(s):  
Kenji KAGITANI ◽  
Koji OSHIKIRI ◽  
Taro KIKUCHI ◽  
Shou MAKINO ◽  
Yoshito SEINO ◽  
...  
Keyword(s):  
Crack Width ◽  
Width Measurement

scholarly journals DYNAMIC BEHAVIOR OF REINFORCED CONCRETE COLUMN UNDER ACCIDENTAL IMPACT

2021 ◽  
Vol 17 (3) ◽  
pp. 120-131
Author(s):  
Sergey Savin ◽  
Vitaly Kolchunov
Keyword(s):  
Reinforced Concrete ◽  
Analytical Solution ◽  
High Speed ◽  
Impact Load ◽  
Dynamic Buckling ◽  
Shock Load ◽  
Dynamic Factor ◽  
Physical Parameters ◽  
Concrete Column ◽  
Reinforced Concrete Column

The analysis of scientific literature shows that to date, the physical parameters of the deformation of reinforced concrete bar structures during their dynamic buckling and the influence of the dissipative properties of the structural system on this process remain insufficiently studied. In this regard, the paper proposes an analytical solution to the problem of dynamic buckling of a reinforced concrete column when it is loaded with an impact load, taking into account the presence of initial geometric and (or) physical imperfections and damping properties of the system, as well as an analysis and assessment of the column deformationparameters based on the obtained analytical solution. An expression for the dynamic deflection of a bar element under its axial loading with a high-speed shock load, taking into account damping, is obtained in an analytical form. For practical calculations in a quasi-static formulation, the paper proposes an expression for the dynamic factor kd of bar structures under axial shock load. A numerical example of calculating a reinforced concrete column using the obtained analytical expressions with and without damping is considered. It was found that the maximum deflection of the elastic axis of the column under high-speed loading was achieved at t = 0.04 s. In this case, the total dynamic deflection taking into account damping was 4.8% less than the deviation without taking into account damping and 1.18 times more than the corresponding static value.

scholarly journals DEVELOPMENT OF A HIGH-SPEED VIDEOGRAMMETRIC MEASUREMENT SYSTEM WITH APPLICATION IN LARGE-SCALE SHAKING TABLE TEST

2019 ◽  
Vol IV-2/W7 ◽  
pp. 33-38
Author(s):  
S. Gao ◽  
Z. Ye ◽  
C. Wei ◽  
X. Liu ◽  
X. Tong
Keyword(s):  
Data Processing ◽  
Measurement System ◽  
High Speed ◽  
Large Scale ◽  
Moving Objects ◽  
Shaking Table Test ◽  
Image Sequences ◽  
Shaking Table ◽  
Dynamic Monitoring ◽  
Observation Network

<p><strong>Abstract.</strong> The high-speed videogrammetric measurement system, which provides a convenient way to capture three-dimensional (3D) dynamic response of moving objects, has been widely used in various applications due to its remarkable advantages including non-contact, flexibility and high precision. This paper presents a distributed high-speed videogrammetric measurement system suitable for monitoring of large-scale structures. The overall framework consists of hardware and software two parts, namely observation network construction and data processing. The core component of the observation network is high-speed cameras to provide multiview image sequences. The data processing part automatically obtains the 3D structural deformations of the key points from the captured image sequences. A distributed parallel processing framework is adopted to speed up the image sequence processing. An empirical experiment was conducted to measure the dynamics of a double-tube five-layer building structure on the shaking table using the presented videogrammetric measurement system. Compared with the high-accuracy total station measurement, the presented system can achieve a sub-millimeter level of coordinates discrepancy. The 3D deformation results demonstrate the potential of the non-contact high-speed videogrammetric measurement system in dynamic monitoring of large-scale shake table tests.</p>

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