Lateral Shear Research Articles

Relationship Between Lateral/Basal Shear Stress Ratio and Structural Vergence of Thrust Wedges: Results From Analogue Modeling and Implications for the Origin of Eastern Sichuan–Xuefeng Fold‐Thrust Belt in South China

AbstractThrust wedges are common in nature, but not all of their origins can be properly explained by the classic Coulomb wedge theory, which considers only a 2D perspective. A few analogue models, however, revealed that lateral shear stress (inherent in both analogue models and nature) may strongly affect the development of thrust wedges and the lateral/basal shear stress (τs/τd) ratio might have controlled the structural vergence of thrust wedge, suggesting that origin of thrust wedges needs to be considered from a 3D perspective. The origin of the Eastern Sichuan–Xuefeng fold‐thrust belt (ESXFTB), which is characterized by two oppositely vergent thrust systems at different crustal levels and may contain another large purely backward‐vergent thrust wedge on the world, is still problematic. Revealing the relationship between τs/τd ratio and structural vergence may prompt a deep understanding of the origin of thrust wedges as well as the ESXFTB. This relationship, however, is still not very clear due to the lack of systematic experiments. For these reasons, we performed systematic experiments of two types of analogue models under different τs/τd ratios. Our model results revealed, for the first time, that structural vergence of thrust wedges lying on a weak décollement may progressively change from frontward (when τs/τd <0.09) to dual (when τs/τd = 0.09–1.15) and then to backward (when τs/τd >1.15) and the two oppositely vergent thrust systems in the ESXFTB can be produced simultaneously by the single northwestward Mesozoic shortening probably due to their apparently different τs/τd ratios.

Analytical model for the activation of off-axis secondary faulting between two dissimilar rock layers

Bimaterial faults can be found in nonhomogeneous rock media between dissimilar rock layers. An analytical model was extended for the right lateral strike-slip fault between two dissimilar rock layers to predict the activated tensile, right and left lateral shear zones around the fault tip. The effect of elastic modulus contrast (E2/E1, the ratio of the Young's moduli of the lower to the upper layer), rupture velocity (c), precompression stress ratio (-ϭxxo/-ϭyyo), residual to peak strength ratio (τr/rp) and fracture energy (G) were considered. Results show that under an intermediate rupture speed of (0.5 of the Rayleigh wave speed): the extension of activated tensile and shear zones depends strongly on the ratio of E2/E1 and it increases with increasing this ratio. The preferred direction of the new branches is little affected by the elastic modulus contrast. Increasing precompression stress ratio encourages right and left lateral shear branching on the compressional side of the fault and decreases the size of activated tensile and shear zones. Under an extreme rupture speed of (0.98 of the Rayleigh wave speed): the mechanism of branching differs, for E2/E1 < 1, the three activated zones are located in the lower layer and there is only a possibility for unilateral branching on the extensional side of the fault. For E2/E1 ≥ 1, right and left lateral shear zones extend to the upper layer (compressional side), which means the possibility of bilateral shear branching on the two sides of the fault. For all values of E2/E1, c, -ϭxxo/-ϭyyo, tensile branches can only be formed in the lower layer on the extensional side of the fault.

Computational investigation of interface printing patterns within 3D printed multilayered scaffolds for osteochondral tissue engineering

Osteoarthritis is a highly prevalent rheumatic musculoskeletal disorder that commonly affects many joints. Repetitive joint overloading perpetuates the damage to the affected cartilage, which undermines the structural integrity of the osteochondral unit. Various tissue engineering strategies have been employed to design multiphasic osteochondral scaffolds that recapitulate layer-specific biomechanical properties, but the inability to fully satisfy mechanical demands within the joint has limited their success. Through computational modeling and extrusion-based bioprinting, we attempted to fabricate a biphasic osteochondral scaffold with improved shear properties and a mechanically strong interface. A 3D stationary solid mechanics model was developed to simulate the effect of lateral shear force on various thermoplastic polymer/hydrogel scaffolds with a patterned interface. Additionally, interfacial shear tests were performed on bioprinted polycaprolactone (PCL)/hydrogel interface scaffolds. The first simulation showed that the PCL/gelatin methacrylate (GelMA) and PCL/polyethylene glycol diacrylate (PEGDA) scaffolds interlocking hydrogel and PCL at interface in a 1:1 ratio possessed the largest average tensile (PCL/GelMA: 80.52 kPa; PCL/PEGDA: 79.75 kPa) and compressive stress (PCL/GelMA: 74.71 kPa; PCL/PEGDA: 73.83 kPa). Although there were significant differences in shear strength between PCL/GelMA and PCL/PEGDA scaffolds, no significant difference was observed among the treatment groups within both scaffold types. Lastly, the hypothetical simulations of potential biphasic 3D printed scaffolds showed that for every order of magnitude decrease in Young’s modulus (E) of the soft bioink, all the scaffolds underwent an exponential increase in average displacement at the cartilage and interface layers. The following work provides valuable insights into the biomechanics of 3D printed osteochondral scaffolds, which will help inform future scaffold designs for enhanced regenerative outcomes.

Geometric controls of tidewater glacier dynamics

Abstract. Retreat of marine outlet glaciers often initiates depletion of inland ice through dynamic adjustments of the upstream glacier. The local topography of a fjord may promote or inhibit such retreat, and therefore fjord geometry constitutes a critical control on ice sheet mass balance. To quantify the processes of ice–topography interactions and enhance the understanding of the dynamics involved, we analyze a multitude of topographic fjord settings and scenarios using the Ice-sheet and Sea-level System Model (ISSM). We systematically study glacier retreat through a variety of artificial fjord geometries and quantify the modeled dynamics directly in relation to topographic features. We find that retreat in an upstream-widening or upstream-deepening fjord does not necessarily promote retreat, as suggested by previous studies. Conversely, it may stabilize a glacier because converging ice flow towards a constriction enhances lateral and basal shear stress gradients. An upstream-narrowing or upstream-shoaling fjord, in turn, may promote retreat since fjord walls or bed provide little stability to the glacier where ice flow diverges. Furthermore, we identify distinct quantitative relationships directly linking grounding line discharge and retreat rate to fjord topography and transfer these results to a long-term study of the retreat of Jakobshavn Isbræ. These findings offer new perspectives on ice–topography interactions and give guidance to an ad hoc assessment of future topographically induced ice loss based on knowledge of the upstream fjord geometry.

Shear direction switching phenomena in twisted nematic liquid crystal cells for novel differential interference contrast imaging systems

AbstractA lateral shear occurs between ordinary and extraordinary rays in general optical uniaxial crystals, and we can observe a double image through the crystal, indicating a typical birefringence phenomenon. Small lateral shears occur in typical liquid crystal (LC) cells under small voltage applications, where the molecular alignment direction is generally inclined. The small lateral shear is useful for differential interference contrast (DIC) imaging systems, although it must be negligible in a typical LC display panel. In particular, unique lateral shearing properties are exhibited by twisted nematic (TN) LC cells, which are popular and important LC display modes. The 45°‐oblique lateral shear occurs according to the direction of the surface molecular alignment, and the inclination direction (+45° or −45°) depends on the molecular twist direction. If it is possible to switch the twist direction in the TN cell, the lateral shear direction can be switched by 90°, and a full DIC imaging system can be attained because the normal DIC system can obtain one‐directional derivative information along the shear direction. In this work, twist direction switching phenomena in TN cells are investigated by applying a magnetic field in the direction parallel to the cell surface.

Shear strain evolution during tension-induced Lüders-type deformation of polycrystalline NiTi plates

This paper reports a new aspect of the Lüders-type deformation of NiTi. This is on the occurrence of lateral shear strains in a tension-induced Lüders deformation process. The phenomenon was studied by means of digital image correlation analysis. It was found that the lateral shear strains occurred in opposite directions within the Lüders band, apparently as an effort to self-accommodate the lateral displacement caused by the shear strains. The Lüders band propagation also changed from a single band mode to a branched mode when the lateral displacement, thus the in-plane bending moment, became too large. The branches, whilst having the same axial normal strain in the loading direction, were formed with opposite shear strains in double alternation between left and right of the sample and between the branches and the gaps between them, thus, to achieve the optimum self-accommodation. In addition, both the axial normal strain field and the lateral shear strain field were nonuniform after the Lüders-type deformation. These findings provide more insight and direct evidence for the explanation of the characteristics of Lüders deformation behaviour of NiTi.

Weakening of the pinning point buttressing Thwaites Glacier, West Antarctica

Abstract. The Thwaites Eastern Ice Shelf buttresses a significant portion of Thwaites Glacier through contact with a pinning point 40 km offshore of the present grounding line. Predicting future rates of Thwaites Glacier’s contribution to sea-level rise depends on the evolution of this pinning point and the resultant change in the ice-shelf stress field since the breakup of the Thwaites Western Glacier Tongue in 2009. Here we use Landsat-8 feature tracking of ice velocity in combination with ice-sheet model perturbation experiments to show how past changes in flow velocity have been governed in large part by changes in lateral shear and pinning point interactions with the Thwaites Western Glacier Tongue. We then use recent satellite altimetry data from ICESat-2 to show that Thwaites Glacier’s grounding line has continued to retreat rapidly; in particular, the grounded area of the pinning point is greatly reduced from earlier mappings in 2014, and grounded ice elevations are continuing to decrease. This loss has created two pinned areas with ice flow now funneled between them. If current rates of surface lowering persist, the Thwaites Eastern Ice Shelf will unpin from the seafloor in less than a decade, despite our finding from airborne radar data that the seafloor underneath the pinning point is about 200 m shallower than previously reported. Advection of relatively thin and mechanically damaged ice onto the remaining portions of the pinning point and feedback mechanisms involving basal melting may further accelerate the unpinning. As a result, ice discharge will likely increase up to 10 % along a 45 km stretch of the grounding line that is currently buttressed by the Thwaites Eastern Ice Shelf.

Fast reconstruction technology of a laser beam spatial transmission characteristic curve.

The traditional multiposition method of the M2 factor measurement system is a good method, but it is relatively time consuming, so it cannot meet the requirements of the transient test of a Gaussian beam. To solve this problem, a quadriwave lateral shearing interferometer and a wavefront construction method based on a difference Zernike polynomial are analyzed. This interferometer uses a special grating to select four replicas of the wavefront, and the interferogram generated by four replicas includes difference wavefront information. Then the difference Zernike polynomial method is used to analyze quadriwave lateral shearing interferograms. The characteristic parameters are obtained after finding the optimal terms of the Zernike polynomials. As a result, the errors of F-number, beam radius, and radius of curvature are 3.7%, 3.8%, and 0.6%, respectively, which verifies this method to calculate parameters of Gaussian beam. In addition, we also find that the shear amount has influence on the reconstructed wavefront. It is showed that as the amount of shear increases from 20 pixels to 90 pixels, the peak-to-valley (P-V) values and RMS values both gradually decrease with a nonlinear relationship, which could be used to decrease the error of wavefront reconstruction further.

Shear response of circular-in-square CFDST members: Experimental investigation and finite element analysis

This paper firstly presented an experimental work of circular-in-square concrete-filled double-skin steel tubular (CFDST) members under lateral shear load. Sixteen circular-in-square CFDST specimens and four concrete-filled steel tubular (CFST) specimens were fabricated and tested. Crucial design parameters considered in this test including shear-span ratio (m = 0.4, 0.6, 0.8 and 1.0) and hollow ratio (χ = 0.46, 0.59, 0.67 and 0.82) were studied and discussed. The load-displacement curve (P-Δ), shear strain-load curve (γ-P), and failure mode of the tests were analyzed in detail. The testing results show that as the shear-span ratio increases, the shear capacity drops significantly with the change of failure modes from brittle shear failure to ductile bending failure. The hollow ratio is of primary importance in the study of shear strength for CFDST specimens. When m is 0.4–0.8, specimens with a larger the hollow ratio experience a lower shear capacity, and however when m = 1.0, specimens with larger the hollow ratio exhibit a higher shear capacity. Furthermore, using experimental work presented in this study as a basis for model verification, corresponding finite element model was developed to further explore the mechanical properties of CFDST specimens subjected to shear load via using software ABAQUS. Finally, the expression was proposed for predicting the shear capacity of circular-in-square CFDST specimens, in which both the shear-span ratio and hollow ratio were considered. It can be found that the predictions are very compatible to the testing results from this study.

Orientation-dependent superelasticity and fatigue of CuAlMn alloy under in situ micromechanical tensile characterization

The in situ micromechanical tensile tests are conducted to characterize the superelastic behaviors for [223], [1214], [325] and [205] oriented Cu67Al24Mn9 micro-slats. The stress-induced martensitic transformations are captured in all textures corresponding to strong crystallographic anisotropy. We propose a one-dimensional constitutive model considering the directional anisotropy of elastic modulus for cubic symmetry and the crystallographic compatibility of twinned martensite. The modeled mechanical behaviors agree with the micromechanical tensile tests well, which suggests that the formation of compatible twins is the primary deformation mechanism. Particularly in the [205] texture, we observed formation of nano-cavities (<100nm) on the lateral surface of the micro-slat. Based on the analysis of compatible martensite twin laminates and fcc slip systems, we theorize that the massive normal elongation and little lateral shear cause the formation, stretching and growth of nano-cavities at nano scales to accommodate the external loads. As a result, the structural and functional fatigue resistance is improved compared to other textures. The experimental and theoretical results in this paper are potentially useful to guide the texture design of Cu-based shape memory alloy for high transformation strain and low functional fatigue.

Numerical investigation of the impact of fracture aperture anisotropy on EGS thermal performance

The impact of anisotropy within spatially-varying fracture apertures on heat transfer in the context of Enhanced Geothermal Systems was investigated. The anisotropic fracture aperture distributions studied included samples from laboratory-scale fractures and additional 100 artificial fracture aperture distributions generated using Sequential Gaussian Simulation. Two flow configurations were investigated. The perpendicular flow configuration had a flow perpendicular to the lateral shear offset direction, while the parallel flow configuration had a flow parallel to the lateral shear offset direction. The thermal performance was simulated numerically using a thermohydraulic model with a 50 mm by 50 mm sheared fracture, typical granitic rock properties, and temperature dependence of fluid density and viscosity.The results showed that 70% of the fracture aperture distributions studied gave rise to favorable thermal performance in the perpendicular flow configuration. It was also observed from this study that the flow-wetted surface area had a direct and significant contribution to the amount of heat extracted. In addition, larger volumetric flow through preferential paths also contributed to more heat extraction and could offset surfaces without large flow-wetted surface areas. The results of this study suggest that placing an injector well in the direction perpendicular to shear or slip may result in favorable thermal performance over a parallel flow configuration.Geometric anisotropy was deduced from the joint roughness coefficient (JRC) and variogram modeling parameters of the datasets studied. High geometric anisotropy results in high differences in thermal drawdown between the flow configurations. Combining the difference in geometric anisotropy and difference in JRCs between the flow configuration could aid in identifying if the thermal performance will be favorable in a given flow configuration.

The Anatolian Diagonal: a broad left lateral shear zone between the North Anatolian Fault Zone and the Aegean / Cyprus Arcs

Recent detailed examination of the internal deformation of the Turkish-Iranian Plateau in the hinterland of Bitlis-Zagros Suture Zone, which is related to the collision of the Arabian and Eurasian plates, indicates multiple intersection points between the right- and left-lateral strike-slip structures explained by an inevitably broad left-lateral strike-slip shear zone, the Anatolian Diagonal. The faults bounding and internally deforming the Anatolian Diagonal were closely examined by using high-resolution satellite images, focal mechanism solutions of the earthquakes, and published seismic reflection data in the offshore areas. The Anatolian Diagonal is a NE-SW trending left-lateral shear zone having a 170 km width between the Central Anatolian and the East Anatolian fault zones and an 850 km length between Erzincan and the Cyprus Arc. It has at least four intersection points with the right-lateral North Anatolian Fault Zone and the Southeast Anatolian-Zagros Fault Zone. As the offshore continuation of the Ecemiş-Deliler Fault of the Anatolian Diagonal, the Biruni Fault reaches the Cyprus Arc and Piri Reis (Mediterranean) Ridge Front west of Cyprus. This structure creates a restraining stepover with the left-lateral Antalya-Kekova Fault Zone and causes NW-SE trending thrusts of the Florence Rise and Antalya Thrust in the Antalya Basin. There is another restraining stepover between the Antalya-Kekova Fault Zone and the Pliny-Strabo Fault Zone, where the thrust-controlled northern margin of Rhodes basin developed. In this neotectonic framework, there is no need for the existence of the highly-debated left-lateral Fethiye-Burdur Fault Zone as an onshore continuation of the Pliny and Strabo faults. In fact, the westerly motion of the Anatolian plate is accommodated by the left-lateral Anatolian Diagonal Shear Zone, Antalya-Kekova Fault Zone and Pliny-Strabo Fault Zone together with the right-lateral North Anatolian Fault Zone.

Surface form error measurement for rough surfaces using an infrared lateral shearing interferometry

The fabrication of a large monolithic mirror or a segmented mirror requires a high throughput that satisfies the time-cost requirement. Particularly, the rough surface properties of grinding pose a challenge for accurate measurement of the surface figure error (SFE). If the SFE during grinding is as small as possible, the material removal volume in the figuring process gets reduced, and the total required time of the fabrication is greatly minimized. In this paper, we propose a new metrology tool called intermediate surface figure error measurement (ISFEM) that can be applied to measurement of SFE for rough surfaces. It consists of a CO2 laser of wavelength 10.6 µm as a light source, a lateral shearing interferometer as a wavefront sensor, and several optical components for beam shaping and imaging. The ISFEM demonstrated its ability to measure the microns to sub-micron rms SFE of the ground surface by testing the samples with a 0.59 µm -1.56 µm rms of surface roughness and a large SFE of about 3 µm rms. The system was applied to the fabrication of an off-axis parabolic mirror of diameter 1.1 m, where it successfully performed as an intermediate metrology between laser tracker measurement for the rough surface and interferometric measurement for the polished surface. The ISFEM obtained measurements from 3.88 µm rms SFE during the fine grinding process and down to 0.38 µm rms during the polishing process. Therefore, we confirmed that the ISFEM provides a unique solution for high throughput for the fabrication of large or multiple segmented mirrors.

Detection of airborne nanoparticles with lateral shearing digital holographic microscopy

In this study, we propose to image the nano-sized particles dispersed in the air with the lateral shearing digital holography technique. Another aim of ours is to determine how long these particles stay in the environment (cabinet, room, air and etc.) by calculating the concentration amounts (CA) in different humidity conditions and what type of particle is given to the cabinet. Binarized phase images reconstructed from the recorded holograms were used to find the CA. The CA was calculated by measuring in a time depended manner. In addition, in this study, the behavior of particulate matter in different humidity conditions was also revealed. It has been clearly demonstrated that the residence time in the air varies depending on the structure of each particulate matter and the behavior of the environment in different humidity conditions. Moreover, images were classified by deep learning based on Convolution Neural Network (CCN) algorithm. The CNN algorithm was trained using binarized phase images and the type of substance dispersed in the air was determined with high accuracy (99%). Unlike the traditional digital holography microscopy techniques used to capture a single microsized sample located between two lamellas, this study reveals successful results obtained with high accuracy that nano-sized particles moving freely in the air can be imaged and the type of particulate matter can be detected. It is thought that the proposed system for the early detection of particles that causes various infectious diseases will lead to future studies in terms of both non-contact and real-time imaging.

Dynamic Analysis of High-Rise Building with Outrigger System under Seismic Loading

The present work has been done by observing the behaviour of outrigger structure using non dimensional parameter α and β under the action of earthquake load. The earthquake load calculation has been done by IS 1893 (Part-1):2016. In the structure, the outriggers and belt truss are placed at two different locations. The location has been decided by the study of many research paper that at top level of the building (i.e., floor no. 40) and other at 0.55H of the building (i.e., floor no. 22). In this study the non-dimension parameter α remain constant and β change their value by varying depth of outrigger beams to compare the analysis result. In this research, a 40-story 3D reinforced concrete structure with plan area of 25.0 m X 25.0 m and height of building is 128 m is considered in modelling. Location of first outrigger at 40th floor and second outrigger at 22th floor (0.55H) of the building is also modelled in CSI ETABS V19.0 software considering the time history analysis of proposed work. The depth of first outrigger beam is taken same as the floor height of the 40th floor and for second outrigger beam the depth of beam varied as one storey, one and half storey and two storey depth of floor. Key parameter discussed in this paper includes the lateral displacement, story drift and Base shear. The conclusion comes from the study is that when the stiffness of outrigger beam with belt truss is increased by increasing the depth from one storey to two storeys then it will increase the overall lateral stiffness of model that control storey drift.

Fast and Calibration-Free Temperature Imaging of Dynamic Flames via Wavelength Modulated Lateral Shearing Interferometry

Temperature distributions of dynamical flames were measured by using a proposed calibration-free wavelength modulated lateral shearing interferometry. A distributed feedback (DFB) laser was modulated in the wavelength as a sawtooth profile. The wrapped flame phase in the images was obtained pixel by pixel by calculating the phase shift between the interference light intensity profiles before and after flame ignition. Phase unwrapping and recovery were adopted to solve the flame phase distribution. The refractive index distribution was reconstructed with the help of Inverse Abel transform. The temperature imaging was further achieved by the ideal gas law and Gladstone-Dale model. Numerical simulations were conducted for performance evaluations. The flame phase, refractive index and temperature distributions were reconstructed with errors of 0.0094, 0.0154 and 0.0958, respectively. Standard deviations were in the magnitude of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> at the presence of Gaussian random noises and showed the noise immunity of the proposed method. In actual experiments, reconstructed temperature distribution of a steady flame generated on a Bunsen burner agreed well with the thermocouple measurements. A dynamical process of flame extinguishment was portrayed at one kilo frames per second. Temporal variation of the flame temperature distribution well reflected the extinguishing process. The entire measurement process did not require prior calibration of the modulated wavelength, and the imaging speed was more than ten times faster than the existing phase modulated interferometer. The proposed method can be used for on-line evaluation of dynamic flames.

Ultraestable spatiotemporal characterization of optical vortices in the visible and near infrared

We show the versatility of the bulk lateral shearing interferometer characterizing complex spatiotemporal structures in different spectral ranges. Specifically, we have characterized constant and timevarying optical vortices in the visible and near infrared spectral ranges respectively. The high stability of the system combined with its spectral versatility will ease the spatiotemporal characterization of ultrafast phenomena.

Cellular properties of human gingival fibroblasts on novel and conventional implant-abutment materials

ObjectivesTo characterize human-gingival-fibroblast-(HGFs) viability, proliferation and adhesion on polymer-infiltrated-ceramic-network-(PICN), polyetheretherketone-(PEEK), hydroxyapatite-reinforced-polyetheretherketone-(HA-PEEK), polyetherketoneketone-(PEKK), as well as conventional titanium-(Ti) and zirconia ceramic-(Zr) implant materials in-vitro. MethodsSix materials (n = 40/group, 240 specimens) were standardized for surface roughness, assessed employing water contact angle measurements (WCA) and loaded with HGFs. HGF viability and proliferation were assessed at 24 and 72 h. Cell adhesion strength was evaluated after 24 h exposure to lateral shear forces using a shaking-device at 320 and 560-rpm.and qualitatively tested by scanning-electron-microscopy-(SEM) at 3, 24 and 72 h. ResultsPICN demonstrated the lowest mean WCA (48.2 ± 6.3º), followed by Zr (73.8 ± 5.1º), while HA-PEEK showed the highest WCA (87.2 ± 1.5º; p ≤ 0.05). After 24 h, Zr showed the highest mean HGFs-viability rate (88 ± 14%), while PEKK showed the lowest one (78 ± 7%). At 72 h, Zr continued to show the highest HGF-viability (80 ± 6%) compared to PEKK (67.5 ± 6%) and PEEK (67%±5). SEM did not reveal differences between different materials with respect to cell attachment at 3, 24 or 72 h. At 320 rpm shaking, HGFs showed to be best attached to PICN (mean%-of-detached-cells ± SD; 26 ± 11%) and worst to PEEK (54 ± 18%). At 560 rpm shaking, Zr showed the least detached cells (32 ± 4%), while HA-PEEK revealed the highest number of detached cells (58 ± 3%; ANOVA/Tukey-post-hoc-test, differences not statistically significant). SignificanceDental implant abutment materials and their wettability strongly affect HGF proliferation and adhesion properties. Although, PICN showed the best wettability properties, Zr exhibited the strongest adhesion strength at high shaking. Within the current study’s limitations, Zr remains the most biocompatible abutment material.

Compensated differential Zernike fitting method for wavefront aberration metrology based on grating lateral shearing.

Lateral shearing based on the grating is one of the classical configurations when measuring the wavefront aberration of optical systems such as the lithographic projection lens. Because the wavefront under test is spherical, but a detector surface is a plane, the coordinate of the wavefront surface will be distorted on the detector surface. As the numerical aperture (NA) of the optics under test increases, the shear ratios at different positions within the shearing region are significantly different due to the coordinate distortion. Therefore, the reconstructed wavefront from the traditional lateral-shearing reconstruction method designed for a fixed shearing ratio will contain a non-negligible error. In this work, we use the ray-tracing method to calculate the shearing ratio distribution in the shearing region and propose a compensated differential Zernike fitting method to solve the coordinate distortion and shearing ratio variation problem. The relative error of the uncompensated result will increase as the NA increases. This error is around 1% for a 0.1 NA, 10% for a 0.3 NA, and over 100% for an NA above 0.7. Compensation for the shearing ratio variation is necessary when the NA is larger than 0.3. The proposed method has been validated by simulations and experiments.

Study on seismic performance of reinforced concrete multi-storey building considering soil-structure interaction effect

The dynamic interaction between structure, foundation, and soil, known as 'soil-structure interaction', determines the seismic response of high-rise buildings susceptible to failure owing to earthquake loads (SSI). Research on SSI in typical reinforced concrete (RC) buildings is very restricted, especially when it comes to combining structural and geotechnical fields of competence. The available code regulations are reviewed to ensure a sufficient design to withstand seismic loads. In this study, Abaqus (Simulia's Abaqus 6.19) software was used to conduct a series of three-dimensional finite element analyses to investigate the effects of high-rise structures' number of stories (20, 25, and 30 stories) on seismic performance as well as the size of raft foundation with SSI effects. The seismic loading input was computed using the El-Centro acceleration time-history record for fixed-base RC buildings and the dual framed-shear wall system fixed to the foundation and soil field. The effects of the height of RC building models, foundation size, and soil type on lateral storey displacement, inter-story drift, natural period, and shear pressures are explored. According to the findings, the number of stories and SSI significantly impact the structural loading of RC high-rise buildings.