Background: In synchrotron radiation computed tomography (SR-CT) of mechanical loading process, accurate reconstruction of finite angle projection information shielded by mechanical loading devices is a bottleneck problem. Objective: For accurate characterization, an experimental strategy for in situ SR-CT mechanical loading test was proposed in this manuscript, which was called "finite angle CT reconstruction

A correction to this paper has been published: https://doi.org/10.1007/s11340-021-00702-z

Background High pressure die casting (HPDC) Mg alloy has a hetero-structure in which the microstructures gradually coarsen from the casting surface to the interior, leading to the different elastic–plastic (E-P) transitional behaviors among the layers. Objective In this paper, we quantitively determined the diverse E-P transitions among the HPDC layers and related them to the microstructural evolution

Background: Application of patterns to enable high-resolution Digital Image Correlation (DIC) at the small scale (μm/nm) is known to be very challenging as techniques developed for the macro- and mesoscale, such as spray painting, cannot be scaled down directly. Moreover, existing nano-patterning techniques all rely on harsh processing steps, based on high temperature, chemicals, physical contact,

Background Friction Stir Welding (FSW) causes intense plastic deformation and consequent thermomechanical interactions resulting in a localised heterogeneous microstructure. To understand the weld mechanical behaviour, it is necessary to identify each microstructural sub-region in the weld. Objective Determine the relationship between the local microstructure and mechanical behaviour of the different

Background Developments in digital image correlation (DIC) in the last decade have made it a practical and effective optical technique for displacement and strain measurement at high temperatures. Objective This overview aims to review the research progress, summarize the experience and provide valuable references for the high-temperature deformation measurement using DIC. Methods We comprehensively

Background Subsurface mechanisms can greatly affect the mechanical behavior of biological materials, but observation of these mechanisms has remained elusive primarily due to unfavorable optical characteristics. Researchers attempt to overcome these limitations by performing experiments in biological mimics like hydrogels, but measurements are generally restricted due to the spatio-temporal limitations

Background It is common practice to use various residual stress measurement methods to complement each other and fully define a through-thickness stress distribution. Incremental hole-drilling (IHD) and X-ray diffraction (XRD) are two of the most widely used techniques. Although IHD readily provides stress data to some depth, the method is susceptible to large stress uncertainties near the surface

Background Digital Image and Volume Correlation (DIC and DVC) are non-contact measurement techniques that are used during mechanical testing for quantitative mapping of full-field displacements. The relatively high noise floor of DIC and DVC, which is exasperated when differentiated to obtain strain fields, often requires some form of filtering. Techniques such as median filters or least-squares fitting

Background High-velocity oxy-fuel (HVOF)-sprayed metallic coating can be used to create a surface layer that plays a significant role in enhancing the overall strength, stiffness, and fatigue life of the treated material. The micro-deformation around a single impacted particle is a critical factor that must be considered for the optimization of the HVOF process. Objective In this study, the micro-deformation

Background Digital image correlation (DIC) has become a superior tool for surface deformation measurement so far. In order to improve its measurement accuracy, different error models have been developed to reveal the cause of various error. Objective An error model unifying the random error and systematic error should be valuable. Method In this paper, a frequency-domain error model for 2D-DIC is established

Background Digital Image Correlation (DIC) is widely used for remote and non-destructive structural health evaluation of infrastructure. Current DIC applications are limited to relatively small areas of structures and require the use of stationary stereo vision camera systems that are not easy to transfer and deploy in remote areas. Objective The enclosed work describes the development and validation

Background Soft tribology is increasingly important in the design and engineering of materials used in robotics, haptics, and biomechanics studies. When patterned surfaces are part of a lubricated tribopair that undergoes sliding and compressive deformation, the patterns experience a bending strain that affects the lubrication film thickness and elastohydrodynamic friction. The contribution of bending

Background Ratcheting is an important mechanical behavior of metals and alloys, which is caused by the repeated accumulations of tensile and compressive strain in circle load. However, the current characterization methods of ratcheting effect are mostly based on standardized testing and uniform data, and more comprehensive field measurement data cannot be used. Objective This paper focuses on how to

Background Dislocation dynamic simulations are intended as a tool to understand and predict the mechanical behavior of metallic materials, but its prediction has never been directly verified by experiments due to differences in specimen strain rate and size. Objective In this work, a comprehensive experimental framework is proposed to attempt direct comparison between experiments and discrete dislocation

Background With the recent increase in digital image correlation (DIC) applications, it is important to improve the computational efficiency of DIC and realize the closed loop control of systems. Objective A real-time three-dimensional (3D) DIC method for large deformation and rotation measurements is proposed in this paper. Methods To solve the problem of initial guess estimation under large deformation

Background Microwave imaging is widely used in many areas involving non-destructive testing, biomedical imaging, radar detection and imaging, etc. However, there is a lack of microwave 3D imaging methods with lateral and depth super-resolution. Objective We propose a microwave near-field 3D super-resolution imaging method based on the near-field scanning microwave microscopy (NSMM) technique, enabling

Background As a full-field optical metrology, projection moiré approach has been widely used in many engineering applications. The modeling of moiré system and the calibration, including the calibration of relationship between the moiré phase and object’s height, and the calibration of optical system parameters, are the key points in this method as they directly determine the measurement accuracy and

Background Load-relaxation under a constant state of deformation is a common characteristic of hydrated materials, including hydrogels and biological tissues. Overall, mechanical response in such materials is a strong function of underlying structure, which in hydrogels depends on whether the gel is formed through physical or chemical cross-linking. In order to use hydrogels in biomedical applications

Background Continuous welded rails (CWR) are subjected to thermal effects that may lead to buckling or fracture during warm or cold seasons, respectively. The modal characteristics (frequency and mode shapes) of CWR may reveal important information about the thermal stress that can be used to prevent rail failures. Objective The primary objective of this study is to prove a contactless method to monitor

Background As new applications demand the synthesis and validation of materials with specific mechanical performance targets, there is a need for improved characterization and understanding of reduced length-scale deformation processes which govern mechanical behavior (i.e., dislocation slip and twinning). The heterogeneous nature of deformation in polycrystalline materials makes it essential to employ

Background The contact and frictional response of a hydrogel is dependent on the polymer structure at the gel surface. Recent work has shown that different mold materials in contact with the gel during polymerization will affect the resulting polymer density. Objective The tribological response of a gel with a ‘brushy’ less-dense polymer surface has not been thoroughly studied. Our goal was to perform

Background Conventional composites used in damping applications exhibit an undesirable tradeoff between stiffness and energy dissipation. Recent research demonstrates that it is possible to simultaneously achieve increased stiffness and energy dissipation for a configuration of a viscoelastic polymer matrix placed in parallel with a negative stiffness structure (NSS). This configuration resulted in

Background The burst testing technique is used to determine the failure hoop stress of tubes that are subjected to internal pressure. In that technique, the tube is subjected to internal high fluid pressure until it bursts. This testing technique is costly and is not suitable if the available tube material is limited. Objective In this paper, a novel design of a ring expansion testing rig is presented

Background The internal strain distribution developing during plastic deformation is important for understanding the mechanical properties of polycrystalline materials. Such distributions may be determined by the microstructural feature tracking method. However, the strain accuracy and the sources of uncertainty of this method are not well quantified yet. Objective Evaluate the accuracy of local strain

Background Given the inherent manufacturing variabilities and potential for in-service damage of composite parts, the identification of the elastic properties of composites is important to ensuring the safety and the proper performance of the part. Objective The primary objective of this manuscript is to determine, nondestructively, the elastic properties of composite parts, whether as in-situ components

Background Soft, biological, and bio-inspired materials are often compositionally heterogeneous and structurally anisotropic, and they frequently feature graded or layered organizations. This design complexity enables exceptional ranges in properties and performance yet complicates a fundamental understanding of the contact mechanics. Recent studies of soft gel layers have relied on Hertzian or Winkler

Background Uncertainty quantifications are required for any measurement result to be meaningful. Objective The present work aims at deriving and comparing a priori estimates of displacement uncertainties in T3-stereocorrelation for a setup to perform high temperature tests. Methods Images acquired prior to the actual experiment (i.e.,at room temperature) were registered using 3-noded triangular elements

Background Digital image correlation (DIC) method is a non-interference and non-contact full-field optical measurement technology. DIC’s measurement accuracy is largely determined by the image acquisition system and the quality of the speckle pattern. Objective Although the optimal speckle pattern has been designed theoretically, the optimization process does not consider the influence of the imaging

Background Additive manufacturing (AM) is becoming increasingly popular, but standards for critical defect sizes and porosity levels have not been fully established. The wide range of flexibility offered by AM is unable to be exploited by designers if they do not have confidence in their components’ mechanical behavior. Objective The goal of this study was to understand how the factors of specimen

Background Transient grating spectroscopy (TGS) is a laser-ultrasonic method allowing measurement of the surface acoustic wave (SAW) velocity in an examined material for a given direction of the wave vector. Objective We explore the capability of TGS for determination of shear elastic coefficients (\(c^\prime\) and \(c_{44}\)) of strongly anisotropic cubic materials. Methods TGS is tested on a set

Background Microstructural features such as grain boundaries play a significant role in the macroscopic plastic response of polycrystalline metals. However, a quantitative link between plastic strain accumulation at grain boundaries and material response in plasticity dominated phenomena is still lacking. Objective Here we seek to develop predictive relations between a material’s granular microstructure

Background An advanced two-dimensional digital image correlation (2D-DIC) using active imaging and telecentric imaging has been proposed to overcome the problems of out-of-plane motion and ambient light variation. Objective Here, the technique is further improved by combining built-in coaxial illumination and telecentric fluorescent imaging to provide quality 2D-DIC measurement even in space-constrained

Background Accelerated development of advanced metals and alloys requires validated relationships between the high throughput indentation measurements and standardized tensile test protocols. Objective The main objective of this paper is to critically evaluate the quantitative relationships between the yield strengths measured in standard tensile tests and the indentation yield strengths obtained from

Background Regional mechanical characterization of pulmonary arteries can be useful in the development of computational models of pulmonary arterial mechanics. Objective We performed a biomechanical and microstructural characterization study of porcine pulmonary arteries, inclusive of the main, left, and right pulmonary arteries (MPA, LPA, and RPA, respectively). Methods The specimens were initially

Background Experimental analyses of the 3D strain field evolution during loading allows for better understanding of deformation and failure mechanisms at the meso- and microscale in different materials. In order to understand the auxetic behaviour and delamination process in paperboard materials during tensile deformation, it is essential to study the out-of-plane component of the strain tensor that

Background Temperature gradients significantly affect the material fatigue process. A reliable and robust test procedure is needed for quantifying the effects of temperature gradients on the evolution of fatigue damage in nickel-based superalloys. Objective The present study aims to develop a radiation heating system for universal material testing machine for simulating thermal gradient mechanical

Background Measurement precision and uncertainty estimation are important factors for all residual stress measurement techniques. The values of these quantities can help to determine whether a particular measurement technique would be viable option. Objective This paper determines the precision of hole-drilling residual stress measurement using repeatability studies and develops an updated uncertainty

The original article was updated to include the missing section from eq. (4) to eq. (8).

Background Understanding the dynamic tensile response of microwave damaged rock is of great significance to promote the development of microwave-assisted hard rock breakage technology. However, most of the current research on this issue is limited to static loading conditions, which is inconsistent with the dynamic stress circumstances encountered in real rock-breaking operations. Objective The objective

Background Because of technical limitations, most experimental studies on the energy-absorbing properties of ballistic fabrics are limited to discrete evaluations based on impact and residual velocities. Consequently, the continuous interaction between a projectile and a target material is still commonly assessed with analytical models or numerical simulations, the validation of which is based on the

Background Metaconcrete is a new concept of concrete, showing marked attenuation properties under impact and blast loading, where traditional aggregates are partially replaced by resonant bi-material inclusions. In a departure from conventional mechanical metamaterials, the inclusions are dispersed randomly as cast in the material. The behavior of metaconcrete at supersonic frequencies has been investigated

Background In the microscopic observation of deforming metals, it is well known that crystallite defects that accommodate strain can occasionally become visible, namely, they introduce image contrast to their locality. For microscopic digital image correlation (DIC) applications, this is typically known as a disturbance. Objective Here, we explore a potential upside of these image-intensity offsets

Background: Digital Image Correlation (DIC) is based on the matching, between reference and deformed state images, of features contained in patterns that are deposited on test sample surfaces. These features are often suitable for a single scale, and there is a current lack of multiscale patterns capable of providing reliable displacement measurements over a wide range of scales. Objective: Here, we

Background Rupture of brain aneurysms is associated with high fatality and morbidity rates. Through remodeling of the collagen matrix, many aneurysms can remain unruptured for decades, despite an enlarging and evolving geometry. Objective Our objective was to explore this adaptive remodeling for the first time in an elastase induced aneurysm model in rabbits. Methods Saccular aneurysms were created

Background Heart valve computational models require high quality geometric input data, commonly obtained using micro-computed tomography. Whether in the open or closed configuration, most studies utilize dry valves, which poses significant challenges including gravitational and surface tension effects along with desiccation induced mechanical changes. Objective These challenges are overcome by scanning

Background Myxomatous mitral valve degeneration is a common cause of mitral regurgitation and is often associated with mitral valve prolapse. With no known targets to pharmacologically treat mitral valve prolapse, surgery is often the only treatment option. Recently, radiofrequency ablation has been proposed as a percutaneous alternative to surgical resection for the reduction of mitral valve leaflet

Background Polymer mechanics and characterization is an active area of research where a keen effort is directed towards gaining a predictive and correlative relationship between the applied loads and the specific conformational motions of the macromolecule chains. Objective Therefore, the objective of this research is to introduce the preliminary results based on a novel technique to in situ probe

Background Measuring the mechanical properties of soft biological tissues in-vitro by using conventional methods (e.g. tension, compression, or indentation) is prone to external testing and sample preparation factors. For example, sample slippage affects the measurement accuracy of mechanical properties of soft biological tissues. In addition, samples have to go through a complex cutting process to

Background Pulmonary artery hypertension (PAH) is a complex disorder that can lead to right heart failure. The generation of caveolin-1 deficient mice (CAV-1−/−) has provided an alternative genetic model to study the mechanisms of pulmonary hypertension. However, the vascular adaptations in these mice have not been characterized. Objective To determine the histological and functional changes in the

Background Hemolysis in sickle cell disease (SCD) releases cell free hemoglobin, which scavenges nitric oxide (NO), leading to pulmonary vascular vasoconstriction, increased pulmonary vascular resistance (PVR), and the development of PH. However, PVR is only one component of right ventricular (RV) afterload. Whether sickled red blood cells increase the total RV afterload, including compliance and wave

Background: Since the mechanical behavior of pantographic metamaterials depends upon the properties of their microstructure, accurate descriptions of unit cells are needed. Objective: The present effort is motivated by this requirement to characterize the detailed deformation of unit cells formed of two orthogonal sets of 3 beams. Methods: Their deformations in a bias extension test were measured via

Background Calcification was recently found to be present in the majority of cerebral aneurysms, though how calcification and the presence or absence of co-localized lipid pools affect failure properties is still unknown. Objective The primary objective is to quantify the biomechanical effect of a macro-calcification with surrounding Near-Calcification Region (NCR) of varying mechanical properties

Background Using a thin-walled tube torsion test to characterize a material’s shear response is a well-known technique; however, the thin walled specimen tends to buckle before reaching large shear deformation and failure. An alternative technique is the surface stress method (Nadai 1950; Wu et al. J Test Eval 20:396–402, 1992), which derives a shear stress-strain curve from the torque-angular displacement

Background Multiaxial dynamic loadings occur in many industrial cases and multiaxial dynamic test development is thus a crucial issue. Objective To meet this challenge, a biaxial compression Hopkinson bar set-up is designed. Methods The set-up consists of a striker, an input bar, an internal output bar and a co-axial external output tube (surrounding the internal bar). The internal output bar measures

Background Mouse models of abdominal aortic aneurysm (AAA) and dissection have proven to be invaluable in the advancement of diagnostics and therapeutics by providing a platform to decipher response variables that are elusive in human populations. One such model involves systemic Angiotensin II (Ang-II) infusion into low density-lipoprotein receptor-deficient (LDLr−/−) mice leading to intramural thrombus

Background Hypertension drives myocardial remodeling, leading to changes in structure, composition and mechanical behavior, including residual stress, which are linked to heart disease progression in a gender-specific manner. Emerging therapies are also targeting constituent-specific pathological features. All previous studies, however, have characterized remodeling in the intact tissue, rather than

Background The quality of Digital Volume Correlation (DVC) full-field displacement measurements depends directly on the characteristics of the X-ray Computed Tomography (XCT) equipment, and scan procedures used to acquire the tomographic images. Objective We seek to experimentally study the effects of XCT equipment and tomographic scan procedures on the quality of these images for DVC analysis, and

Background: Subcritical crack growth can occur in a brittle material when the stress intensity factor is smaller than the fracture toughness if an oxidizing agent (such as water) is present at the crack tip. Objective: We present a novel bi-material beam specimen which can measure environmentally assisted crack growth rates. The specimen is “self-loaded” by residual stress and requires no external

Background The non-uniform distribution of atherosclerosis within the arterial system is widely attributed to variation in haemodynamic wall shear stress. It may also depend on variation in pressure-induced stresses and strains within the arterial wall; these have been less widely investigated, at least in part because of a lack of suitable techniques. Objectives Here we show that local arterial strain