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Although silicon is the preferred choice for microelectromechanical systems (MEMS) piezoresistive pressure sensors, such devices are not preferred for application in harsh environmental conditions due to the exponential increase in leakage current with temperature. To alleviate such shortcomings of silicon-based pressure sensors in extreme conditions including elevated temperature and intense vibration, this study strives to shift focus from core complementary metal–oxide–semiconductor (CMOS) materials to silicon carbide. In this work, we adopt an analytical and simulation approach to model and analyze various characteristics of such silicon carbide piezoresistive sensors and determine an optimal design. A square diaphragm is modeled using the analytical expressions for a thin plate in combination with small-deflection theory, providing quick insight for estimation of critical parameters and thus the behavior of the pressure sensor. Both clamped and freely supported edge conditions of the diaphragm are explored. Although many studies and discussions are available on the rigidly supported loading condition, the freely supported edge condition for a square diaphragm has received little attention. The deflection, stress, strain, and sensitivity of the square diaphragm under both loading conditions are reported herein then compared to understand which of the two loading conditions results in more significant outputs.

In this paper, the buckling behaviour of rectangular and skew plates with elastically restrained edges subjected to non-uniform mechanical edge loading is investigated. An analysis method is developed for calculating the critical buckling load of plates using the Ritz method under non-uniform mechanical edge loading, in which the shape function is expressed as Legendre polynomials. The in-plane stress distribution under non-uniform mechanical edge loading is defined by the pre-buckling analysis. Contributions of elastic boundary conditions are taken into accounted by giving different edge spring stiffnesses. The proposed method for buckling analysis of plates is validated by the comparison of exiting results in literature. Finally, the effects of the edge restrained stiffness, non-uniform edge loading, skew angle, aspect ratio and combined compression-shear load are discussed by parametric analysis.

Porous materials are increasingly used in laminated composite shallow shells to reduce weight while maintaining structural performance, making it essential to understand how porosity affects buckling behavior. Simultaneously, the presence of an orthotropic Winkler–Pasternak foundation provides lateral and shear restraint that can significantly influence stability, particularly for shells with complex geometries or non-uniform stiffness distributions. Unlike previous studies that focused solely on the buckling of porous shells under non-uniform loads, this work integrates the stabilizing effects of an orthotropic Winkler-Pasternak foundation. New equilibrium equations are derived to capture the complex interaction between the shell's porosity, the non-uniform stress field, and the foundation's shear/normal restraints. This study investigates the buckling of porous laminated doubly curved shallow shells (PO-LDSs) resting on an orthotropic Winkler-Pasternak foundation using a higher-order shear deformation theory. The shallow shell's layers are composed of porous material with four porosity distributions (UDP, NUDP1–3), and the shell is subjected to five compressive loading patterns (U-CL, TR-CL, TG-CL, P-CL, S-CL). The pre-buckling analysis of non-uniform loading patterns is conducted using the stress function and by minimizing the membrane strain energy. The governing PDEs are transformed into a linear system of equations using Galerkin's method. A parametric study is conducted to investigate the impact of porosity, geometry, fiber orientation, orthotropic foundation, non-uniform edge compressions, and foundation orthotropy angles on the buckling of porous orthotropic laminated shallow shells. The results reveal that the critical buckling load increases monotonically with foundation stiffness, enhancing the buckling capacity by up to 36% for spherical shells (SS) and 51% for hyperbolic paraboloidal shells (HPS). Fiber orientation, orthotropy angles of the foundation, and porosity distribution are found to significantly modulate the critical buckling load; notably, strong foundation orthotropy can alter the buckling resistance by up to 20%. Furthermore, the foundation mitigates sensitivity to extreme fiber angles and asymmetric porosity distributions, reducing the porosity-induced stiffness penalty by approximately 12% to 14%. Additionally, as flatter shells exhibit reduced geometric stiffness, the relative contribution of the foundation support increases by up to 37%. These quantitative findings provide robust design insights for optimizing porous laminated shells under various loading and foundation conditions.

The buckling and vibration characteristics of stiffened plates with cutout subjected to in-plane partial edge loadings at the plate boundary are studied using finite element method. Buckling loads and vibration frequencies are determined for different plate and cutout aspect ratios, various boundary conditions, partial edge loading at different locations, cutout ratios, various parameters of stiffeners by varying the number, size and location of the stiffeners. The analysis presented determines the stresses all over the region for different kinds of loading and edge conditions. In the structural modelling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. The buckling and vibration characteristics are discussed and the free vibration results available in the literature for stiffened plates with/without cutout are compared.

The prediction of the hip joint force (HJF) is a fundamental factor for the prevention of edge loading in total hip arthroplasty. Naturally, the loading of the liner of the acetabular component depends on the HJF acting on the artificial joint. In contrast to dynamic musculoskeletal models, static models for HJF prediction do not require motion analysis of the patient. However, patient-specific adaptability and validity of static models have to be scrutinized. In this study, a modular framework for HJF prediction using static models is introduced to compare the results of different cadaver templates that are the basis of most static and dynamic models, and different scaling laws for the patient-specific adaptation with in vivo HJF of ten patients for one-leg stance and level walking. The results revealed the significant effect of the underlying cadaver template used for the prediction of the HJF (p < 0.01). A higher degree of patient-specific scaling of the cadaver template often did not significantly reduce the prediction error. Three static models with the lowest prediction errors were compared to results of dynamic models from literature. The prediction error of the peak HJF of the static models (median absolute errors below 15% body weight in magnitude and below 5° in direction) was similar in magnitude and even smaller in direction compared to dynamic models. The necessary reduction of a load-based target zone for the prevention of edge loading due to the uncertainty of the HJF prediction has to be considered in the preoperative planning. The framework for HJF prediction is openly accessible at https://github.com/RWTHmediTEC/HipJointForceModel.

While total hip arthroplasty does generally improve patient quality of life, current systems can still yield atypical forces, premature component wear, and abnormal kinematics compared to native joints. Specifically, common complications include instability, separation, sliding, and edge loading within the hip joint. Unfortunately, evaluating potential solutions to these issues can be costly and time-consuming. Fortunately, mathematical modeling is an accurate and efficient tool that can be used to evaluate potential solutions. A forward dynamics mathematical model of the hip allows users to virtually insert a hip implant into a theoretical patient and observe the predicted postoperative mechanics. The objective of this study is therefore to develop, validate, and use a fully functional forward solution mathematical model that allows for a comparison between various hip implant designs and a determination of factors leading to in vivo hip separation, instability, and edge loading. The model presented herein has been validated kinetically against telemetric data and kinematically against fluoroscopic data. It was determined through this research that shifting of the joint rotation center during total hip arthroplasty has the potential to yield postoperative instability, and surgical errors can exacerbate these outcomes. However, the relationships between subject-specific joint shifting and hip instability are extremely complex, and therefore it becomes essential for surgeons to focus on implanting components as accurately as possible to minimize these risks.

Purpose Kinematically aligned (KA) TKA strives to restore native limb and knee alignments without ligament release with the premise that knee function likewise will be closely restored to native to the extent enabled by the components used. This study determined differences in anterior–posterior (AP) tibial contact locations of a KA TKA performed with asymmetric, fixed bearing, posterior cruciate-retaining (PCR) components from those of the native contralateral knee and also determined the incidence of posterior rim contact of the tibial insert during a deep knee bend and a step-up. Methods Both knees were imaged using single-plane fluoroscopy for 25 patients with a calipered KA TKA and a native knee in the contralateral limb. AP tibial contact locations in each compartment were determined following 3D model-to-2D image registration. Differences in mean AP tibial contact locations in each compartment between the KA TKA knees and the native contralateral knees were analysed. Contact locations either on or beyond the most posterior point of the tibial insert determined the occurrence of posterior rim contact. Results Mean AP tibial contact locations for both native and KA TKA knees remained relatively centred in the medial compartment but moved posterior in the lateral compartment during flexion. In both the medial and lateral compartments, differences in mean AP tibial contact locations between the KA TKA knees and the native contralateral knees were more posterior and greatest at 0° flexion for both activities (4 mm, p  = 0.0009 and 7 mm, p  < 0.0001 for deep knee bend and 6 mm, p  < 0.0001 and 8 mm, p  < 0.0001 for step-up in the medial and lateral compartments, respectively). The incidence of posterior rim contact of the tibial insert was 16% (4 of 25 patients) but the lowest Oxford Knee Score was 43 for these patients. The median Oxford Knee Score for all patients was 46 (out of 48). Conclusions Calipered KA TKA with asymmetric, fixed bearing, PCR components resulted in mean AP tibial contact locations which were relatively centred in the compartments and differed at most from those of the native contralateral knee by approximately 15% of the AP dimension of a mid-sized tibial baseplate. Although posterior rim contact occurred in some patients, all such patients had high patient-reported outcome scores. Level of evidence Therapeutic, Level III.

Edge loading can negatively impact the biomechanics and long-term performance of hip replacements. Although edge loading has been widely investigated for hard-on-hard articulations, limited work has been conducted for hard-on-soft combinations. The aim of the present study was to investigate edge loading and its effect on the contact mechanics of a modular metal-on-polyethylene (MoP) total hip replacement (THR). A three-dimensional finite element model was developed based on a modular MoP bearing. Different cup inclination angles and head lateral microseparation were modelled and their effect on the contact mechanics of the modular MoP hip replacement were examined. The results showed that lateral microseparation caused loading of the head on the rim of the cup, which produced substantial increases in the maximum von Mises stress in the polyethylene liner and the maximum contact pressure on both the articulating surface and backside surface of the liner. Plastic deformation of the liner was observed under both standard conditions and microseparation conditions, however, the maximum equivalent plastic strain in the liner under microseparation conditions of 2000µm was predicted to be approximately six times that under standard conditions. The study has indicated that correct positioning the components to avoid edge loading is likely to be important clinically even for hard-on-soft bearings for THR.

This study focuses on the thermomechanical optimization of buckling resistance in laminated composite plate with a hole. The goal is to maximize the critical buckling load by identifying optimal fiber orientations within the layers using the Bonobo Optimizer Algorithm (BOA). The first-order shear deformation theory (FSDT) is employed to determine elastic buckling loads under combined thermomechanical loading. Numerical investigations are conducted for various parameters, including uniform temperature rises, edge loading conditions, support configurations, hole size ratios, load ratios, and geometric proportions. The results showed that these parameteres play a vital role in the the buckling load optimization of laminate composite plate with a hole. The study shows CCCC and SFSF boundary conditions yield the highest and lowest buckling loads, respectively. Critical buckling load decreases with temperature rise. Plates without cut-outs outperform those with cut-outs, and shorter plates under negative temperature rise achieve maximum buckling load. Uniform loading results in the lowest buckling capacity due to its larger loading area.

This paper presents a number of thrust-collar-specific effects to consider when simulating the elastohydrodynamic lubrication state. Plate bending can lead to edge loading and can be considered via an FEM model of the solids. When bending is of no concern, the effect of the close outside edge needs to be corrected in half-space deformation theory. Track heating requires a unique version of the Carslaw/Jaeger flash temperature solution for curved trajectories. Especially, the adapted treatment of stiffness effects leads to vastly different results in, e.g., lubrication gap height.