Measurement of strain distributions in mouse femora with 3D-digital speckle pattern interferometry

Abstract

Bone is a mechanosensitive tissue that adapts its mass, architecture and mechanical properties to external loading. Appropriate mechanical loads offer an effective means to stimulate bone remodeling and prevent bone loss. A role of in situ strain in bone is considered essential in enhancement of bone formation, and establishing a quantitative relationship between 3D strain distributions and a rate of local bone formation is important. Digital speckle pattern interferometry (DSPI) can achieve whole-field, non-contacting measurements of microscopic deformation for highresolution determination of 3D strain distributions. However, the current system does not allow us to derive accurate strain distributions because of complex surface contours inherent to biological samples. Through development of a custom-made piezoelectric loading device as well as a new DSPIbased force calibration system, we built an advanced DSPI system and integrated local contour information to deformation data. Using a mouse femur in response to a knee loading modality as a model system, we determined 3D strain distributions and discussed effectiveness and limitations of the described system. KeywordsBone strain; digital speckle pattern interferometry (DSPI); ESPI; mechanical loading; deformation and contour information

Design Strategy of Minipig Molars Using Electronic Speckle Pattern Interferometry: Comparison of Deformation under Load between the Tooth‐Mandible Complex and the Isolated Tooth

“…Before testing, the complex was embedded in acrylic (JET acrylic, Lang Dental MFG) within a metal holder leaving the tooth crown and the upper third of the bone exposed. The tooth was coated with a thin coat of white spray, a common procedure in optical testing [37]. After testing, the section was extracted from its holder and the bone was carefully removed from the root using a water-cooled dental drill.…”

Universal optical setup for phase-shifting and spatial-carrier digital speckle pattern interferometry

“…These phase differences are wrapped due to the arc tangent operation expressed in Eqs. (3) and (9). The real phase differences are finally obtained after image smoothing and phase unwrap operations are performed [21].…”

“…PS-DSPI utilizes the interference between an object beam from a measuring target and a reference beam from a fixed surface to measure the out-of-plane deformation, and the interference between object and reference beams from the measuring target via different paths to measure in-plane deformations [8,9]. 3D deformation measurement is then realized by combining one optical setup for out-of-plane deformation measurement and two optical setups for in-plane deformation measurement together.…”

Experimental Investigation of Delamination Growth in Composite Laminates under a Compressive Load

“…The local last squares fitting method to calculate the true strain field in presence of holes or crack areas has been investigated in [30] while the detection of strain singularity due to artificial delamination by using the DIC technique has been considered in [31,32]. The DIC technique has been used to study the crack growth behavior in [33], the impact induced damage in composite structures under compressive load in [34], and finally, holes in composite laminates and the bonded repairs performance also under tensile load in [35].…”