Displacement Study of a Large-Scale Freeform Timber Plate Structure Using a Total Station and a Terrestrial Laser Scanner

Recent advances in timber construction have led to the realization of complex timber plate structures assembled with wood-wood connections. Although advanced numerical modelling tools have been developed to perform their structural analysis, limited experimental tests have been carried out on large-scale structures. However, experimental investigations remain necessary to better understand their mechanical behaviour and assess the numerical models developed. In this paper, static loading tests performed on timber plate shells of about 25 m span are reported. Displacements were measured at 16 target positions on the structure using a total station and on its entire bottom surface using a terrestrial laser scanner. Both methods were compared to each other and to a finite element model in which the semi-rigidity of the connections was represented by springs. Total station measurements provided more consistent results than point clouds, which nonetheless allowed the visualization of displacement fields. Results predicted by the model were found to be in good agreement with the measurements compared to a rigid model. The semi-rigid behaviour of the connections was therefore proven to be crucial to precisely predict the behaviour of the structure. Furthermore, large variations were observed between as-built and designed geometries due to the accumulation of fabrication and construction tolerances.

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Experimental Nondestructive Test for Estimation of Buckling Load on Unstiffened Cylindrical Shells Using Vibration Correlation Technique

Shock and Vibration ◽

10.1155/2015/729684 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 8

Author(s):

Kaspars Kalnins ◽

Mariano A. Arbelo ◽

Olgerts Ozolins ◽

Eduards Skukis ◽

Saullo G. P. Castro ◽

...

Keyword(s):

Large Scale ◽

Numerical Models ◽

Cylindrical Shells ◽

Laser Scanner ◽

Experimental Tests ◽

Buckling Load ◽

Correlation Technique ◽

Thin Walled Structures ◽

Instability Point ◽

Thin Walled

Nondestructive methods, to calculate the buckling load of imperfection sensitive thin-walled structures, such as large-scale aerospace structures, are one of the most important techniques for the evaluation of new structures and validation of numerical models. The vibration correlation technique (VCT) allows determining the buckling load for several types of structures without reaching the instability point, but this technique is still under development for thin-walled plates and shells. This paper presents and discusses an experimental verification of a novel approach using vibration correlation technique for the prediction of realistic buckling loads of unstiffened cylindrical shells loaded under axial compression. Four different test structures were manufactured and loaded up to buckling: two composite laminated cylindrical shells and two stainless steel cylinders. In order to characterize a relationship with the applied load, the first natural frequency of vibration and mode shape is measured during testing using a 3D laser scanner. The proposed vibration correlation technique allows one to predict the experimental buckling load with a very good approximation without actually reaching the instability point. Additional experimental tests and numerical models are currently under development to further validate the proposed approach for composite and metallic conical structures.

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Registration of large-scale terrestrial laser scanner point clouds: A review and benchmark

ISPRS Journal of Photogrammetry and Remote Sensing ◽

10.1016/j.isprsjprs.2020.03.013 ◽

2020 ◽

Vol 163 ◽

pp. 327-342 ◽

Cited By ~ 10

Author(s):

Zhen Dong ◽

Fuxun Liang ◽

Bisheng Yang ◽

Yusheng Xu ◽

Yufu Zang ◽

...

Keyword(s):

Large Scale ◽

Laser Scanner ◽

Point Clouds ◽

Terrestrial Laser Scanner

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STUDI PEMANFAATAN TEKNOLOGI TERRESTRIAL LASER SCANNER UNTUK MENGHITUNG VOLUME PENGUPASAN OVERBURDEN DI PIT 2 ELEKTRIFIKASI BANKO BARAT PT. BUKIT ASAM, TBK. TANJUNG ENIM, SUMATERA SELATAN

Prosiding Temu Profesi Tahunan PERHAPI ◽

10.36986/ptptp.v0i0.5 ◽

2019 ◽

Vol 1 (1) ◽

pp. 47-60

Author(s):

Ezil Defri Maharfi ◽

Taufik Arief ◽

Diana Purbasari

Keyword(s):

Point Cloud ◽

Laser Scanner ◽

Point Clouds ◽

Terrestrial Laser Scanner ◽

Total Station ◽

Cloud Data ◽

Data Point ◽

Cut And Fill

PT. Bukit Asam, Tbk. merupakan perusahaan pertambangan batubara yang terletak di Tanjung Enim, Kabupaten Muara Enim, Provinsi Sumatera Selatan. Selama ini pengukuran volume pengupasan overburden dilakukan menggunakan alat Total Station. Pengukuran area overburden yang luas dan bentuk permukaan yang beragam menggunakan Total Station dinilai kurang efektif karena lamanya waktu yang dibutuhkan dan rendahnya tingkat ketelitian. Oleh kerena itu, diperlukan alat yang dapat mengukur volume dengan cepat serta menghasilkan data ukuran volume yang detail dan dengan kerapatan tinggi. Salah satunya yaitu penggunaan Terrestrial Laser Scanner. Metode yang digunakan dalam melakukan pengukuran yaitu metode occupation and backsight. Pengukuran menggunakan metode occupation and backsight diperlukan dua titik yang telah diketahui koordinatnya yang digunakan sebagai titik berdiri alat dan untuk titik acuan (backsight). Metode registrasi yang digunakan yaitu metode occupation and backsight dan metode cloud to cloud. Data point clouds yang telah diregistrasi perlu dilakukan filtering untuk menghilangkan noise dan objek asing yang bukan lapisan overburden. Perhitungan volume dilakukan dengan metode cut and fill terhadap model tiga dimensi dari point cloud yang terbentuk. Data hasil perhitungan didapatkan volume pengupasan overburden selama Desember 2017 sampai dengan Mei 2018 adalah sebesar 847.937 m3, dengan rincian 255.700 m3 di bulan Desember 2017, 299.120 m3 di bulan Januari 2018, 227.543 m3 di Bulan Februari 2018 dan 65.572 m3 di bulan Maret 2018.

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Point-Based Shape Monitoring of Plate Bending for Large-Scale Storage Tanks

Volume 1: 37th Computers and Information in Engineering Conference ◽

10.1115/detc2017-68105 ◽

2017 ◽

Author(s):

Kenta Fukano ◽

Hiroshi Masuda ◽

Ataru Kobayashi ◽

Kazuki Ikeda

Keyword(s):

Large Scale ◽

Laser Scanner ◽

Point Clouds ◽

Steel Plates ◽

Plate Bending ◽

Terrestrial Laser Scanner ◽

Storage Tanks ◽

Flat Plates ◽

Flat Shape ◽

Shape Monitoring

Storage tanks are constructed using thousands of large curved steel plates, which are manufactured from flat plates. In conventional manufacturing of curved plates, operators fit wooden templates to specific positions on steel plates and measure differences between the current shape and the template. However, it is costly to create many wooden templates for a variety of plates. In addition, it is time-consuming and requires skills to precisely place wooden templates on specific positions to measure differences. In this paper, we discuss methods to automatically calculate differences of shapes during bending processes without wooden templates. We capture dense points on steel plates using a terrestrial laser scanner, and analyze shapes of curved plates using point-clouds. In our method, the system extracts only the points on curved plates, and tracks the amount of deformation on reference lines defined on the plates. Corresponding positions between intermediate curved plates and the original flat shape are calculated using mesh flattening techniques. In our experiments, our method could calculate the amount of differences of steel plates in reasonable performance and precision.

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Fitting Terrestrial Laser Scanner Point Clouds with T-Splines: Local Refinement Strategy for Rigid Body Motion

Remote Sensing ◽

10.3390/rs13132494 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2494

Author(s):

Gaël Kermarrec ◽

Niklas Schild ◽

Jan Hartmann

Keyword(s):

Point Cloud ◽

Goodness Of Fit ◽

Laser Scanner ◽

Point Clouds ◽

Statistical Testing ◽

Computational Time ◽

Terrestrial Laser Scanner ◽

Reference Surface ◽

Local Refinement ◽

Surface Approximation

T-splines have recently been introduced to represent objects of arbitrary shapes using a smaller number of control points than the conventional non-uniform rational B-splines (NURBS) or B-spline representatizons in computer-aided design, computer graphics and reverse engineering. They are flexible in representing complex surface shapes and economic in terms of parameters as they enable local refinement. This property is a great advantage when dense, scattered and noisy point clouds are approximated using least squares fitting, such as those from a terrestrial laser scanner (TLS). Unfortunately, when it comes to assessing the goodness of fit of the surface approximation with a real dataset, only a noisy point cloud can be approximated: (i) a low root mean squared error (RMSE) can be linked with an overfitting, i.e., a fitting of the noise, and should be correspondingly avoided, and (ii) a high RMSE is synonymous with a lack of details. To address the challenge of judging the approximation, the reference surface should be entirely known: this can be solved by printing a mathematically defined T-splines reference surface in three dimensions (3D) and modeling the artefacts induced by the 3D printing. Once scanned under different configurations, it is possible to assess the goodness of fit of the approximation for a noisy and potentially gappy point cloud and compare it with the traditional but less flexible NURBS. The advantages of T-splines local refinement open the door for further applications within a geodetic context such as rigorous statistical testing of deformation. Two different scans from a slightly deformed object were approximated; we found that more than 40% of the computational time could be saved without affecting the goodness of fit of the surface approximation by using the same mesh for the two epochs.

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Comparison of Depth Camera and Terrestrial Laser Scanner in Monitoring Structural Deflections

Sensors ◽

10.3390/s21010201 ◽

2020 ◽

Vol 21 (1) ◽

pp. 201

Author(s):

Michael Bekele Maru ◽

Donghwan Lee ◽

Kassahun Demissie Tola ◽

Seunghee Park

Keyword(s):

Optical Sensors ◽

Point Cloud ◽

Three Dimensional ◽

Laser Scanner ◽

Point Clouds ◽

Depth Camera ◽

Terrestrial Laser Scanner ◽

Cloud Data ◽

3D Point Clouds ◽

3D Information

Modeling a structure in the virtual world using three-dimensional (3D) information enhances our understanding, while also aiding in the visualization, of how a structure reacts to any disturbance. Generally, 3D point clouds are used for determining structural behavioral changes. Light detection and ranging (LiDAR) is one of the crucial ways by which a 3D point cloud dataset can be generated. Additionally, 3D cameras are commonly used to develop a point cloud containing many points on the external surface of an object around it. The main objective of this study was to compare the performance of optical sensors, namely a depth camera (DC) and terrestrial laser scanner (TLS) in estimating structural deflection. We also utilized bilateral filtering techniques, which are commonly used in image processing, on the point cloud data for enhancing their accuracy and increasing the application prospects of these sensors in structure health monitoring. The results from these sensors were validated by comparing them with the outputs from a linear variable differential transformer sensor, which was mounted on the beam during an indoor experiment. The results showed that the datasets obtained from both the sensors were acceptable for nominal deflections of 3 mm and above because the error range was less than ±10%. However, the result obtained from the TLS were better than those obtained from the DC.

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UAV and terrestrial laser scanner data processing for large scale topographic mapping

Mongolian Geoscientist ◽

10.5564/mgs.v50i0.1329 ◽

2020 ◽

Vol 50 ◽

pp. 63-73

Author(s):

Ganbold Ulziisaikhan ◽

Dash Oyuntsetseg

Keyword(s):

Data Processing ◽

Spatial Data ◽

Large Scale ◽

Laser Scanner ◽

Measurement Technology ◽

Topographic Mapping ◽

Terrestrial Laser Scanner ◽

Scanner Data ◽

Processing Scheme ◽

Digital Elevation

Integrating spatial data from different sources results in visualization, which is the last step in the process of digital basic topographic map creation. Digital elevation model and visualization will used for geomorphological mapping, geospatial database, urban planning and etc. Large scale topographic mapping in the world countries is really a prominent challenge in geospatial industries today. The purpose of this work is to integrate laser scanner data with the ones generated by aerial photogrammetry from UAV, to produce detailed maps that can used by geodetic engineers to optimize their analysis. In addition, terrestrial - based LiDAR scans and UAV photogrammetric data were collected in Sharga hill in the north zone of Mongolia. In this paper, different measurement technology and processing software systems combined for topographic mapping in the data processing scheme. UTM (Universal Transverse Mercator) projected coordinate system calculated in WGS84 reference ellipsoid. Feature compilation involving terrestrial laser scanner data and UAV data will integrated to offer Digital Elevation Models (DEM) as the main interest of the topographic mapping activity. Used UAV generate high-resolution orthomosaics and detailed 3D models of areas where no data, are available. That result issued to create topographic maps with a scale of 1:1000 of geodetic measurements. Preliminary results indicate that discontinuity data collection from UAV closely matches the data collected using laser scanner.

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