Three-dimensional surface characterization for orthopaedic joint prostheses.

This research study focuses on the experimental analysis of the three-dimensional (3D) surface topography and surface roughness of the workpiece machined with ultrasonic vibration assisted turning (UAT) in comparison to conventional turning (CT). For the challenge that machining difficulties of 304 austenitic stainless steel (ASS 304) and high demands for the machined surface quality and machining precision represent, starting with cutting principle and processing technology, the ultrasonic vibration method is employed to scheme out a machining system of ultrasonic vibration assisted turning (MS-UAT). The experiments for turning the workpiece of ASS 304 are conducted with and without ultrasonic vibration using the designed MS-UAT, and then the 3D morphology evaluation parametersSaandSqare applied to characterize and analyse the machined surface. The experimental results obtained demonstrate that the process parameters in UAT of ASS 304 have obvious effect on the 3D surface topography and surface roughness of machined workpiece, and the appropriate choice of various process parameters, including ultrasonic amplitude, feed rate, depth of cut, and cutting speed, can enhance the machined surface quality efficiently to make the machining effect of UAT much better than that of CT.

A new approach is developed in this paper to predict the three-dimensional gear surface topography in the process of gear generating grinding, and a parametric equation is derived to describe the trajectory on the tooth surface of gear left by each ideal sphere grain. To determine the final three-dimensional gear surface topography generated by thousands of single abrasive grain with randomly distributed locations and protrusion heights, an algorithm for geometrical analysis is developed to systematically process the gear surface profile. There are two steps for this method: the first step is to map the cutting path to the tooth profile in each generating stroke, and the second stage is to combine these generated surface topographies together and trim them in an appropriate manner to create a whole tooth surface. The simulation results show that the surface roughness is increasing monotonously along the tooth profile direction, which is confirmed by the experiment. In order to get uniform surface roughness, a non-uniform generation method is introduced by dividing the entire arc length into isometric n segments. With the use of this method, the surface roughness in each part is essentially equal. Besides, the surface roughness improves about 16.3 % when the machining time is the same, and the reduction of machining time is 42.8 % when the surface roughness of addendum is equal.

Nickel–titanium (NiTi) alloys are extensively utilised in aerospace, biomedical, and precision engineering applications due to their distinctive functional properties, including superelasticity and the shape memory effect. However, their poor machinability and strong sensitivity to cutting conditions render it challenging to obtain surfaces with stable functional integrity. The present study investigates the impact of diverse cooling methodologies—namely dry machining, minimum quantity lubrication (MQL) and cryogenic cooling employing liquid nitrogen (LN2)—on the three-dimensional (3D) surface topography of NiTi alloy following milling. A comprehensive set of three-dimensional surface roughness parameters was employed to quantify the surface geometry and evaluate its potential functional performance. The findings indicated that both dry milling and MQL yielded significantly divergent surface parameters, suggesting unstable surface formation, which may potentially compromise component durability. MQL frequently resulted in topographies that were functionally detrimental and characterised by high parameter dispersion. In contrast, cryogenic cooling (LN2) resulted in the most homogeneous surface topography, as evidenced by the lowest dispersion of 3D roughness indicators. To strengthen the analysis, a Taguchi–TOPSIS multi-criteria optimisation was also performed on ten 3D surface parameters, enabling an integrated ranking of all machining trials. The optimisation process confirmed the superior performance of cryogenic machining, with LN2 conditions achieving the highest overall surface quality index.

Elemental surface topography information in microscopic material characterization contributes to a better understanding of surfaces, interfaces, substrates, and their applications. Here, a general approach based on microbeam proton-induced X-ray emission (micro-PIXE) to reconstruct the three-dimensional (3D) elemental surface topography using the annular multisegment silicon drift detector has been demonstrated. The proposed method includes four main steps: acquiring four two-dimensional elemental concentration maps using the multichannel spectrometer, reconstructing the local inclination angle from the atomic model of ion-matter interaction, calculating the two independent topography gradient components, and numerical surface topography integration. In this study, the general algorithm to obtain the gradient components has been successfully tested on a four-segment configuration to reconstruct the 3D surface topography of compound alloys with different microstructure scales. In synchrotron and accelerator facilities dealing with elemental X-ray mapping where the development of customized multisegment detectors is needed, the introduced method is applicable to elemental surface/interface roughness reconstruction in microscale for cultural heritage samples, fusion plasma-facing materials, and microelectronic devices.

We present the spectral element method to simulate elastic-wave propagation in realistic geological structures involving complieated free-surface topography and material interfaces for two- and three-dimensional geometries. The spectral element method introduced here is a high-order variational method for the spatial approximation of elastic-wave equations. The mass matrix is diagonal by construction in this method, which drastically reduces the computational cost and allows an efficient parallel implementation. Absorbing boundary conditions are introduced in variational form to simulate unbounded physical domains. The time discretization is based on an energy-momentum conserving scheme that can be put into a classical explicit-implicit predictor/multi-corrector format. Long-term energy conservation and stability properties are illustrated as well as the efficiency of the absorbing conditions. The associated Courant condition behaves as ΔtC < O (nel−1/ndN−2), with nel the number of elements, nd the spatial dimension, and N the polynomial order. In practice, a spatial sampling of approximately 5 points per wavelength is found to be very accurate when working with a polynomial degree of N = 8. The accuracy of the method is shown by comparing the spectral element solution to analytical solutions of the classical two-dimensional (2D) problems of Lamb and Garvin. The flexibility of the method is then illustrated by studying more realistic 2D models involving realistic geometries and complex free-boundary conditions. Very accurate modeling of Rayleigh-wave propagation, surface diffraction, and Rayleigh-to-body-wave mode conversion associated with the free-surface curvature are obtained at low computational cost. The method is shown to provide an efficient tool to study the diffraction of elastic waves by three-dimensional (3D) surface topographies and the associated local effects on strong ground motion. Complex amplification patterns, both in space and time, are shown to occur even for a gentle hill topography. Extension to a heterogeneous hill structure is considered. The efficient implementation on parallel distributed memory architectures will allow to perform real-time visualization and interactive physical investigations of 3D amplification phenomena for seismic risk assessment.

Chapter 25 - 3D Surface Topographies in Tritiated Media

Scanning ion conductance microscopy for visualizing the three-dimensional surface topography of cells and tissues

HighlightsSoil particle shapes were statistically analyzed, and four representative particles were obtained.A particle model was established using three-dimensional non-contact surface topography.This study used a response surface design method to calibrate significant soil parameters.The simulation parameters were verified by rotary tiller experiment.Abstract. The discrete element method (DEM) has broad prospects for application in soil-tool simulations. To ensure the reliability of simulations, appropriate simulation parameters and particle modeling are essential. Therefore, in this article, a method combining simulation and actual tests is proposed to calibrate the critical soil parameters. First, the effect of soil particle shape on particle contact was considered. Soil particle shapes were statistically analyzed using an improved GrabCut algorithm and k-means algorithm. Four representative soil particles were obtained. Second, a soil particle model was established by microscope and three-dimensional non-contact surface topography. Finally, taking the angle of repose as the response value, the three parameters with significant effects on the angle of repose, i.e., soil shear modulus, Hertz-Mindlin with Johnson-Kendall-Roberts contact model (JKR), and soil-soil restitution coefficient, were obtained via a Plackett-Burman experiment. The optimal value intervals of the significant parameters were determined by the steepest climbing test. A polynomial regression model between the angle of repose and the three significant parameters was established with a Box-Behnken experiment using three factors and three levels. The interactions between the three significant parameters were not significant, as revealed by response surface analysis. The optimal values of the significant parameters were obtained by taking the actual angle of repose as the target and resulted in a soil shear module of 9.8 MPa, JKR of 0.063, and soil-soil restitution coefficient of 0.478. To verify the reliability of the calibrated parameters, the soil angles of repose from the simulation and from actual tests were compared and analyzed. For a simulated angle of repose of 38.5°, the actual angle of repose was 38.6°, and the relative error was 0.26%. DEM was also used to simulate a rotary tiller with the calibrated parameters. The maximum error of the simulated soil throwing angle was less than 10% when compared with the actual throwing angle. The experimental results showed that the calibrated parameters were accurate and can provide a reference for the selection of soil discrete element parameters. Keywords: Angle of repose, Numerical simulation, Parameter calibration, Shape survey, Soil.

Abrasive wear is a prevalent failure issue in the drilling environment that frequently hampers the reliability and longevity of downhole tools. This study investigated the friction and wear behavior of common drilling materials (nitrided 38 chromium-molybdenum-aluminum (38CrMoAl) steel against 10 cobalt-tungsten-carbon (10Co-WC) cemented carbide) under two conditions (with or without silicon-oxygen (SiO2) particles). The influence of abrasive particles on the coefficient of friction, wear loss, wear surface morphology, and wear mechanisms is discussed in detail. The results indicated that the dispersion of abrasive particles between the contact surfaces reduced the coefficient of friction by approximately 15–25% under loads ranging from 200 to 1,000 N, enhancing the frictional performance. However, this came at the cost of increased wear loss. The wear loss of 38CrMoAl steel increased by 60–80% in the presence of SiO2 particles. The discrepancy between wear mass (measured by weighing) and wear volume (obtained by three-dimensional surface topography) reached up to 40%, highlighting the complex interplay of particle embedding and drilling fluid adsorption. Surface topography studies showed that abrasive particles enhanced lubrication film coverage at lower loads but also induced material spalling. At higher loads (800–1,000 N), the formation of a stable lubricating film reduced wear loss by 20–30%, regardless of abrasive particles presence. Chemical analysis confirmed the generation of anti-friction oxides and chlorides on worn surfaces, while their content decreased by 15–20% due to lubrication film disruption under abrasive particle conditions. The study provides quantitative insights for optimizing downhole tool materials and operational parameters in abrasive drilling environments.

In many applications, the onset of damage occurs at the component surface due to plastic deformation, fretting, wear, corrosion, or crack nucleation. One result of these processes is a change in the surface topography. Therefore, the first step in nondestructive evaluation of a component is a thorough evaluation of the surface conditions. Inspection techniques that characterize the damage extent on the surface often present the results as a fraction of the component surface area. For damage originating from environmental or mechanical conditions, the severity of the defect or damage can also be described quantitatively by the three-dimensional surface topography. When using many common inspection methods, information regarding the depth of penetration into the surface layers, or protrusion above the surface is difficult to obtain. In addition, when the defects are of submicron or nanometer scale, high resolution three-dimensional inspection techniques are required.

Simulation of wheel surface topography is one key aspect of modeling the grinding process. A three-dimensional wheel topography model not only makes the simulated wheel topography more close to the real situation, but also benefits evaluation of wheel machinability and wears condition. This paper presents a physical model for simulation of three-dimensional wheel surface topography. Wheel structural components, grain shape, angle distribution of cutting edges, and the binding materials are considered in the model. Feasibility of the model is indicated by the simulation examples.

Part IV - Visualization techniques and parameters for characterizing three-dimensional surface topography

Determination of the in vivo contact areas in diarthrodial joints can provide valuable clinical data for diagnosing joint malalignments and assessing the outcome of surgical procedures which alter the contact mechanics of a joint. Examples of such procedures include patellar realignment (e.g., lateral release, medial plication, vastus medialis obliquus advancement, Elmslie-Trillat tuberosity transfer) and partial meniscectomies in the knee, or rotator cuff repairs and anterior capsular tightening in the shoulder. Magnetic resonance imaging (MRI) presents the greatest potential for determining such in situ contact areas noninvasively. Indeed, a recent study has described such a procedure (Hobatho et al., 1994), using a finite element code for reconstructing geometric models of articular surfaces, and employing the proximity analysis of Soslowsky et al. (1992) for contact area determination. In the present study, we describe our own methodology for imaging cadaver and patient joints with MRI, reconstructing their three-dimensional articular surface topographies, and determining the joint contact areas.

Aim:To analyze surface roughness and three-dimensional (3D) scanning topography parameters of zirconia implants before and after photofunctionalization by atomic force microscopy (AFM).Materials and Methods:Ten commercially available zirconia implants five each in the study and control group were taken. The study group was subjected to ultraviolet (UV) radiation for 48 h using the shorter wavelength of 254 nm. After washing all the implants with 70% alcohol and drying, 3D surface topography and roughness parameters were analyzed using CSC 17 probe AFM at three different magnifications 25 μm, 50 μm, and 80 μm, respectively.Results:The surface topography and calculated mean amplitude, spatial, and hybrid parameters of the study group were higher than the control group (P < 0.05) in all three magnifications. Up to scale depth and peak value for the study and control group were (−0.4–0.4: −2-1) (−0.75 to 0.6:−1–1.3) (−0.75-−0.5: −1.5-1.3) for the study and control group at 25, 50, and 80 μm magnification, respectively. This indicates that photofunctionalization increased surface roughness of Zirconia implants to desirable extent.Conclusion:There is a definite difference in the quantitative topographic characteristics with zirconia implants being microroughned after photofunctionalization (UV treatment).

: Surfaces that modify their texture (potentially multiscale) in response to either direct control or automatic feedback from external cues (solar light intensity, temperature, incoming waves, etc.) are particularly attractive for military applications as they could be used to change radar, acoustic, thermal or optical signatures to fulfill mission-specific objectives. A natural question would be: how does one design a surface that can dynamically change shape and have its texture smoothly and reversibly reconfigured into specified complex three-dimensional patterns at specific spatial scales? How to control the deformation of active elements made of metamaterials to obtain these textured patterns? The goal of this project was to provide a proof-of-concept answer to this question and, by doing so, effectively bridging the gap between the integration of metamaterials and the design of reconfigurable active structures. A robust computational modeling platform was developed based on non-linear finite element and optimization procedures to design and optimize patterned surfaces by using a clever combination of materials, structural layers, boundary and loading conditions (active controls). The idea was to control three-dimensional surfaces by exploiting their local buckling/wrinkling/folding characteristics triggered by smooth deformation of active reinforcement elements. The proof-of-concept approach was successfully demonstrated. It is possible to deform the surface of a multilayer soft structure with a high level of control to match a given target three-dimensional surface topography by inducing controlled localized buckling. The multiphysics computational platform that was developed is general and can accommodate various types of active materials acting as controllable actuators.