3-D reconstruction by extended depth-of-field in failure analysis – Case study I: Qualitative fractographic investigation of fractured bolts in a partial valve

Hein, Luis Rogério de Oliveira; Campos, Kamila Amato de; Caltabiano, Pietro Carelli Reis de Oliveira; Horovistiz, A.L.

doi:10.1016/j.engfailanal.2009.09.012

Cited by 8 publications

(4 citation statements)

References 6 publications

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“…The selection of the parameters of microscopy and image acquisition had the criterion of optimizing the parameters for extended depth-of-field method. These issues are explained in detail in a previous article[28]. It was used a Nikon-Eclipse LV150 microscope, a reflected Light microscope, with objective lenses for extended working distances Thus, all pictures throughout the sliding surfaces were acquired with spatial resolution of 1260 960 pixels, with a 50X objective (numerical aperture of 0.9) was used to obtain 500 total magnification under brightfield illumination, using green filter.…”

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confidence: 99%

3-D reconstruction by extended depth-of-field in tribological analysis: Fractal approach of sliding surface in Polyamide66 with glass fiber reinforcement

2019

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confidence: 99%

3-D reconstruction by extended depth-of-field in tribological analysis: Fractal approach of sliding surface in Polyamide66 with glass fiber reinforcement

2019

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“…The output of this method is a fully focused image and an elevation map where in Z axis is between 0–255 pixels. It is explained in detail in Hein et al 16…”

Section: Methodsmentioning

confidence: 99%

“…The output of this method is a fully focused image and an elevation map where in Z axis is between 0-255 pixels. It is explained in detail in Hein et al 16 Regions of the worn surface of the samples were pictured with a digital camera in an optical microscope at regular displacement intervals. In each of the regions, stacks of pictures were obtained with a vertical lens shift range between 1μm and 2μm.…”

Section: Optical Microscopy Image Acquisition and 3-d Topographic Rec...mentioning

confidence: 99%

Digital representation of the wear behaviour of Ti-6Al-4V and Ti-6Al-7Nb biomaterial alloys: A fractal analysis of the worn surface

Almeida

Horovistiz

Davim

2023

Proceedings of the Institution of Mechanical Engineers, Part J:

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Currently, Ti-6Al-4V alloy is one of the most used materials in biomedical devices, namely in orthopedic prothesis, thanks to its outstanding properties. However, its composition contains vanadium ions, considered toxic to the human body. Since the 1980s, there has been a growing effort to replace this alloy with less toxic alternatives. A promising candidate is the Ti-6Al-7Nb alloy. There are relatively few studies on the surface properties of this alloy, on the other hand, the knowledge of its tribological performance is of great importance for the use of this alloy in biomedical applications. Digital tribology has great potential in a quantitative inspection of wear in materials engineering. Methodologies of surface inspection, such as fractal description, can explain the relationship between microstructural, tribological parameters, and surface roughness. In this work, the inspection of the fractal behavior of worn surfaces of both Ti-6Al-4V and Ti-6Al-7Nb samples was carried out. Tribological tests were performed in a block-on-disk tribometer, using AISI 1045 steel as antagonist material, under different conditions. The fractal values were correlated to tribological parameters and the evolution of morphological aspects along the surface. Elevation maps of the sliding surfaces were built from pictures obtained from optical microscopy (OM). The “Extended depth from focus”, (EDF) reconstruction method, allowed the ordering of stacks of images to conduct a quantitative investigation of the behavior of surfaces.

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“…Then, the depth of the pixel point P(x, y) can be solved by finding the maximum of F z :

depth = arg max false(F_{z} false), z_{1} \leq z \leq z_{n} .

According to the focus measure method principle, 3D reconstruction based on this method is divided into the spatial and frequency domain methods. At present, several techniques based on the spatial domain method have been proposed, such as the shape from focus (SFF) method (Nakagawa & Nayar, ) under the assumption of a Gaussian defocus model, stack focuser method (Hein, ) and model‐based method (Aguet et al ., ). The problem of focus variation is regarded as a convolutional optimization problem of the object texture and shape by the space domain method.…”

Section: Related Workmentioning

confidence: 99%

Nonmechanical and multiview 3D measurement microscope for workpiece with large slope and complex geometry

Zhang

2018

Journal of Microscopy

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3-D reconstruction by extended depth-of-field in failure analysis – Case study I: Qualitative fractographic investigation of fractured bolts in a partial valve

Cited by 8 publications

References 6 publications

3-D reconstruction by extended depth-of-field in tribological analysis: Fractal approach of sliding surface in Polyamide66 with glass fiber reinforcement

3-D reconstruction by extended depth-of-field in tribological analysis: Fractal approach of sliding surface in Polyamide66 with glass fiber reinforcement

Digital representation of the wear behaviour of Ti-6Al-4V and Ti-6Al-7Nb biomaterial alloys: A fractal analysis of the worn surface

Nonmechanical and multiview 3D measurement microscope for workpiece with large slope and complex geometry

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