Application of a Multi-Camera Stereo DIC Set-up to Assess Strain Fields in an Erichsen Test: Methodology and Validation

Strain ◽  
2013 ◽  
Vol 49 (2) ◽  
pp. 190-198 ◽  
Author(s):  
Y. Wang ◽  
P. Lava ◽  
S. Coppieters ◽  
P. V. Houtte ◽  
D. Debruyne
Keyword(s):  
Strain Fields ◽  
Test Methodology ◽  
Set Up ◽  
Erichsen Test

Improved Strake Design for Vortex Induced Motions of Spar Platforms

2005 ◽  
Author(s):  
Mehernosh Irani ◽  
Lyle Finn
Keyword(s):  
Model Test ◽  
Model Tests ◽  
Test Results ◽  
Test Program ◽  
Test Set ◽  
Test Methodology ◽  
Spar Platforms ◽  
Truss Spar ◽  
Set Up

An extensive model test program was conducted to explore the effectiveness of alternate strake designs to reduce Truss Spar VIV response. Different strake configurations were tested to minimize VIV response. The paper presents results of the model tests. The model test set-up is described, important parameters that are modeled (including hull and truss geometry, strake configuration, mass and mooring properties) and considerations of instrumentation and test methodology are discussed. The paper also describes the analysis of the test results and shows the effectiveness of new strake design. The present results are compared with VIV response of existing Truss Spars with conventional strake design.

Characterization of Strain Fields Around Weld Defects

1987 ◽  
Vol 109 (3) ◽  
pp. 226-229
Author(s):  
S. A. Chavez ◽  
V. A. Deason
Keyword(s):  
Surface Defect ◽  
Local Strain ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Strain Gages ◽  
Strain Fields ◽  
Full Field ◽  
Strain Data ◽  
Set Up

Moire interferometry is used as an alternate technique to resistance strain gages in finding full-field, local strain response of weldments to applied loads. The principles of moire interferometry and the experimental set-up are explained. Data from the two techniques are compared, with no major discrepancies. The strain field around a surface defect is analyzed using moire data. It is concluded that the moire technique is useful for obtaining full-field strain data in welds.

scholarly journals Visualization of an internal sand displacement field around a laterally loaded vertical pile

2021 ◽  
Author(s):  
Ranga Walakulu Arachchi
Keyword(s):  
Displacement Field ◽  
Laser Light ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Displacement Fields ◽  
Strain Fields ◽  
Transparent Soil ◽  
Optical Test ◽  
Set Up ◽  
Laterally Loaded

In this research, an internal sand displacement field around a laterally loaded vertical pile is visualized using transparent soil and an image processing technique called digital image cross-correlation (DIC). DIC is a region-based image processing technique which can calculate the displacement field between two images. Transparent soil is made of silica gel with a pore fluid having the same refractive index. Transparent soil has been studied to have the strength and deformation properties similar to natural soil. An optical test set-up is developed to capture the images during loading. This optical test set-up consists of a camera, a laser light, a line generator lens, a loading frame, a Plexiglas mould, and a PC. The saturated fine sand in loose condition is modeled in this research. A laser light sheet is generated to slice the transparent soil model by passing a laser beam through the line generator lens. A distinctive laser speckle pattern is generated through the interaction between the laser light and transparent soil. A series of images are taken from the camera while a scaled pile is being loaded laterally. The displacement fields are calculated by cross-correlating two consecutive images and the corresponding strain fields are deduced from the displacement fields. The development of both displacement and strain fields is investigated by studying deformation and strains at different loading stages. The test results are similar to the published data. This research improves the understanding of soil movement around a laterally loaded pile. It also advances the physical modeling technique using transparent soil.

scholarly journals Visualization of an internal sand displacement field around a laterally loaded vertical pile

2021 ◽  
Author(s):  
Ranga Walakulu Arachchi
Keyword(s):  
Displacement Field ◽  
Laser Light ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Displacement Fields ◽  
Strain Fields ◽  
Transparent Soil ◽  
Optical Test ◽  
Set Up ◽  
Laterally Loaded

In this research, an internal sand displacement field around a laterally loaded vertical pile is visualized using transparent soil and an image processing technique called digital image cross-correlation (DIC). DIC is a region-based image processing technique which can calculate the displacement field between two images. Transparent soil is made of silica gel with a pore fluid having the same refractive index. Transparent soil has been studied to have the strength and deformation properties similar to natural soil. An optical test set-up is developed to capture the images during loading. This optical test set-up consists of a camera, a laser light, a line generator lens, a loading frame, a Plexiglas mould, and a PC. The saturated fine sand in loose condition is modeled in this research. A laser light sheet is generated to slice the transparent soil model by passing a laser beam through the line generator lens. A distinctive laser speckle pattern is generated through the interaction between the laser light and transparent soil. A series of images are taken from the camera while a scaled pile is being loaded laterally. The displacement fields are calculated by cross-correlating two consecutive images and the corresponding strain fields are deduced from the displacement fields. The development of both displacement and strain fields is investigated by studying deformation and strains at different loading stages. The test results are similar to the published data. This research improves the understanding of soil movement around a laterally loaded pile. It also advances the physical modeling technique using transparent soil.

Optical study of the secondary absorption edge in type l a diamonds

1979 ◽  
Vol 365 (1720) ◽  
pp. 75-94 ◽  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Absorption Edge ◽  
Ground State ◽  
Uniaxial Stress ◽  
Optical Study ◽  
Strain Fields ◽  
Degenerate Ground State ◽  
Intense Absorption ◽  
Set Up

Most natural diamonds contain A aggregates (substitutional pairs) of nitrogen atoms which give rise to intense absorption at hv > 30300 cm -1 (3.75 eV). This paper suggests that the shape of the edge is consistent with its arising in transitions localized at the A aggregates, and not, as commonly assumed, in ionizing transitions. The effects on the edge of uniaxial stresses are reported and analysed quantitatively, showing that three transitions at the foot of the edge occur from a common non-degenerate ground state to one non-degenerate excited state (at 30307 cm -1 ) and to two doubly degenerate excited states (at 31465, 31 680 cm -1 ) at the trigonal A aggregate. By regarding these transitions as the zero phonon lines of three vibronic progressions, the shape and temperature dependence of the edge may be explained semi-quantitatively. The secondary edge is also shown to be self broadened through the strain fields set up by the A aggregates themselves; the magnitude of this broadening may be understood with use of the uniaxial stress data.

Some Aspects of Vortex Induced Motions of a Multi-Column Floater

2015 ◽  
Author(s):  
Mehernosh Irani ◽  
Tim Jennings ◽  
Jeff Geyer ◽  
Evan Krueger
Keyword(s):  
Model Test ◽  
Floating Platform ◽  
Test Program ◽  
Test Setup ◽  
Damping Characteristics ◽  
Test Methodology ◽  
Induced Motion ◽  
Set Up ◽  
Stiffness And Damping ◽  
First Time

An extensive model test program was conducted to explore the effect of various parameters on the Vortex Induced Motion (VIM) response of a four column semi-submersible (Semi) floating platform. The paper describes the model test set-up, important parameters that were modeled (including hull geometry, mass, stiffness and damping properties) and considerations of instrumentation and test methodology. The damping contributions from the moorings and risers have traditionally not been included in a VIM model test setup. This is the first time that the damping characteristics of the moorings and risers are systematically evaluated and included in the model test setup. This paper describes the calculation of the full-scale mooring and riser damping characteristics and, the design and construction of an innovative model test damping mechanism. Besides damping, the effect of varying the Semi draft and external hull appurtenances were also evaluated.

scholarly journals Performance of wood and wood-based materials regarding fungal decay

2020 ◽  
Vol 172 ◽  
pp. 20010
Author(s):  
Michiel Vanpachtenbeke ◽  
Jan Van den Bulcke ◽  
Joris Van Acker ◽  
Staf Roels
Keyword(s):  
Energy Efficiency ◽  
Fungal Growth ◽  
Wood Decay ◽  
International Literature ◽  
Fungal Decay ◽  
Timber Frame ◽  
Test Methodology ◽  
Set Up ◽  
Moisture Conditions ◽  
Frame Construction

Due to the increasingly stringent energy efficiency requirements, timber frame houses are becoming more and more popular across Europe. Depending on the circumstances, timber frame walls might be exposed to high relative humidity or condensation conditions, leading to a risk of fungal degradation. In order to assess the durability of a timber frame construction in a reliable way, a clear view on the potential risk of fungal growth is essential. Various experiments are reported in literature to define the minimal moisture threshold for fungal decay, yet all very different in set-up and hence leading to contradictory conclusions. Therefore, the present paper aims at a contribution to a better understanding of the influence of moisture conditions on the onset and progress of wood decay in timber frame walls. Based on the information that is still lacking in international literature, a new test methodology has been elaborated within this work and is reported in this paper.

Hot Tearing in Cast Aluminum Alloys

2011 ◽  
Vol 690 ◽  
pp. 355-358 ◽  
Author(s):  
Shimin Li ◽  
Diran Apelian ◽  
Kumar Sadayappan
Keyword(s):  
Aluminum Alloys ◽  
Mold Temperature ◽  
Light Metal ◽  
Hot Tearing ◽  
Test Method ◽  
Cast Aluminum ◽  
Test Methodology ◽  
Cast Aluminum Alloys ◽  
Thermomechanical Simulation ◽  
Set Up

MPI and CANMET, both members of the Light Metal Alliance, launched a research project to study hot tearing in aluminum alloys. In this project, a reliable test method to quantitatively evaluate hot tearing was developed, and the processing variables affecting hot tearing tendency were also investigated. This paper summarizes the outcomes of this work from the following aspects: 1) Critical literature survey; 2) Experimental set-up, test methodology and procedures; 3) Effects of mold temperature and pouring temperature; 4) Effect of grain refinement; 5) Thermomechanical simulation of hot tearing.

scholarly journals Investigation of the Fracture Mechanics Properties of Small Tubes from Oxide Dispersion Strengthened Steels

2019 ◽  
Vol 69 (12) ◽  
pp. 3533-3536
Author(s):  
Alexandru Nitu ◽  
Marioara Abrudeanu ◽  
Vasile Radu
Keyword(s):  
Fracture Mechanics ◽  
Mechanical Test ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Loading Test ◽  
Test Methodology ◽  
Geometric Function ◽  
Set Up ◽  
Gen Iv ◽  
Project Objectives

The paper presents one part from the RATEN ICN contribution to the European FP7 MatISSE Project objectives, which is focused on the fracture mechanics properties of small tubes made from ODS steels (Oxide Dispersion Strengthened steels). The ODS tubes are foreseen as cladding tubes for gen IV reactors, and therefore the mechanical properties are very important for working in the most aggressive environment (irradiation and high temperatures) during the gen IV reactor operation. The fracture toughness, KIC, could be obtained for tubes with small diameters by means of the PLT-type mechanical test (acronym for Pin-Loading Test). This kind of test is a non-standard (ASTM) mechanical test, and during last decade it is still worldwide under development. The specific specimens for PLT-tests has been prepared from ODS tubes, which were provided to the project by the CEA France, a partner in the FP 7 MatISSE, in two different compositions: Fe -9cr ODS and Fe -14 Cr ODS. The paper highlights the PLT experimental test methodology, starting with obtaining of the geometric function, description of the experimental set-up and results processing.

Research on Stress-Strain Field and Fatigue Lifetime of the Hot Stamping Die

2010 ◽  
Vol 34-35 ◽  
pp. 1630-1634 ◽  
Author(s):  
Lei Zhang ◽  
Guo Qun Zhao ◽  
Hui Ping Li
Keyword(s):  
Strain Field ◽  
Process Model ◽  
Hot Stamping ◽  
Mechanical Analysis ◽  
Stress And Strain ◽  
Fatigue Lifetime ◽  
Strain Fields ◽  
Stamping Die ◽  
Set Up ◽  
Thermal Mechanical Analysis

In hot stamping process, the die suffers complex thermal mechanical loads. In this paper, the process model and the materials model were set up. And with the example of U-channel forming, a coupled thermal-mechanical analysis is performed with ABAQUS. According to the simulation result, the stress and strain fields of the die show a great uneven distribution in place and time. And the explanation for the non-uniform was given out in this paper. Finally, the fatigue life of the die was evaluated, and the suggestions were proved for optimizing the fatigue lifetime of hot stamping die.

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