Joint Stress Research Articles

A Novel Locking Buttress Plate Designed for Simultaneous Medial and Posterolateral Tibial Plateau Fractures: Concept and Comparative Finite Element Analysis.

The complex tibial plateau fractures involving both medial and posterolateral columns are of frequent occurrence in clinics, but the existing fixation system cannot deal with medial and posterolateral fragments simultaneously. Therefore, a novel locking buttress plate named as medial and posterior column plate (MPCP) was designed in this study to fix the simultaneous medial and posterolateral tibial plateau fractures. Meanwhile, the comparative finite element analysis (FEA) was conducted to investigate the discrepancy between MPCP and traditional multiple plates (MP + PLP) in their biomechanical characteristics. Two 3D finite element models of simultaneous medial and posterolateral tibial plateau fracture fixed with MPCP and MP + PLP system, respectively, was constructed. To imitate the axial stress of knee joint in ordinary life, diverse axial forces with 100, 500, 1000, and 1500 N were applied in the two fixation models, and then the equivalent displacement and stress nephograms and values were obtained. The similar trend of displacement and stress increasing with the loads was observed in the two fixation models. However, several heterogeneities of displacement and stress distribution were found in the two fixation models. The max displacement and von Mises stress values of plates, screws, and fragments in the MPCP fixation model were significantly smaller than that in the MP + PLP fixation model, except for the max-shear stress values. As a single locking buttress plate, the MPCP system showed the excellent benefit on improving the stability of the simultaneous medial and posterolateral tibial plateau fractures, compared with the traditional double plate fixation system. However, the excessive shear stress around screw holes should be paid attention to prevent trabecular microfracture and screw loosening.

Effects of curvature direction on friction stir welding lap joint of aluminum alloy “S” curved surface

In this paper, the friction stir welding (FSW) of single curvature and double curvature “S” curved surface lap joints were realized using split-type pressing blocks fixture and robotic system with welding parameter 1400 rpm, 150 mm/min. By finite element method (FEM) and axial force analysis, the effects of curvature direction on friction stir welding lap joint of 5083 aluminum alloy “S” curved surface is explored. The results show that Z-axis curvature direction has important influence on joint forming. Z-axis positive curvature makes the actual axial compressive force smaller than the device input, which decreases the interface stress of the lap joint and increases the tendency of upper plate weld edges bending deformation and the probability of interface defects. So the joint mechanical properties are reduced, and the tensile load can be as low as 1.5 kN. Z-axis negative curvature makes the actual axial compressive force greater than the device input, which increases the interface stress of the lap joint. Meanwhile, it decreases the tendency of upper plate weld edges bending deformation and leads to the interface defects disappearing. So the joint mechanical properties are good, and the tensile load can be more than 2.4 kN. For Y-axis curvature direction, its impact is mainly shown in changing the direction of resultant force FR. The inclination of force FR is helpful to eliminate the interface defects of the joint. At the same time, it will cause inconsistent stress between the advancing side (AS) and the retreating side (RS) of the joint interface, which is the reason that the double-curvature lap joint welding process is unstable.

Inhibition of knee joint sensory afferents alters covariation across strides between quadriceps muscles during locomotion.

Sport-related injuries to articular structures often alter the sensory information conveyed by joint structures to the nervous system. However, the role of joint sensory afferents in motor control is still unclear. Here, we evaluate the role of knee joint sensory afferents in the control of quadriceps muscles, hypothesizing that such sensory information modulates control strategies that limit patellofemoreal joint loading. We compared locomotor kinematics and muscle activity before and after inhibition of knee sensory afferents by injection of lidocaine into the knee capsule of rats. We evaluated whether this inhibition reduced the strength of correlation between the activity of vastus medialis (VM) and vastus lateralis (VL) both across strides and within each stride, coordination patterns that limit net mediolateral patellofemoral forces. We also evaluated whether this inhibition altered correlations among the other quadriceps muscle activity, the time-profiles of individual EMG envelopes, or movement kinematics. Neither the EMG envelopes nor limb kinematics was affected by the inhibition of knee sensory afferents. This perturbation also did not affect the correlations between VM and VL, suggesting that the regulation of patellofemoral joint loading is mediated by different mechanisms. However, inhibition of knee sensory afferents caused a significant reduction in the correlation between vastus intermedius (VI) and both VM and VL across, but not within, strides. Knee joint sensory afferents may therefore modulate the coordination between the vasti muscles but only at coarse time scales. Injuries compromising joint afferents might result in altered muscle coordination, potentially leading to persistent internal joint stresses and strains.NEW & NOTEWORTHY Sensory afferents originating from knee joint receptors provide the nervous system with information about the internal state of the joint. In this study, we show that these sensory signals are used to modulate the covariations among the activity of a subset of vasti muscles across strides of locomotion. Sport-related injuries that damage joint receptors may therefore compromise these mechanisms of muscle coordination, potentially leading to persistent internal joint stresses and strains.

Validation of a personalized ligament-constraining discrete element framework for computing ankle joint contact mechanics

Background and ObjectiveComputer simulations of joint contact mechanics have great merit to improve our current understanding of articular ankle pathology. Owed to its computational simplicity, discrete element analysis (DEA) is an encouraging alternative to finite element analysis (FEA). However, previous DEA models lack subject-specific anatomy and may oversimplify the biomechanics of the ankle. The objective of this study was to develop and validate a personalized DEA framework that permits movement of the fibula and incorporates personalized cartilage thickness as well as ligamentous constraints. MethodsA linear and non-linear DEA framework, representing cartilage as compressive springs, was established, verified, and validated. Three-dimensional (3D) bony ankle models were constructed from cadaveric lower limb CT scans imaged during application of weight (85 kg) and/or torque (10 Nm). These 3D models were used to generate cartilage thickness and ligament insertion sites based on a previously validated statistical shape model. Ligaments were modelled as non-linear tension-only springs. Validation of contact stress prediction was performed using a simple, axially constrained tibiotalar DEA model against an equivalent FEA model. Validation of ligamentous constraints compared the final position of the ankle mortise to that of the cadaver after application of torque and sequential ligament sectioning. Finally, a combined ligamentous-constraining DEA model was validated for predicted contact stress against an equivalent ligament-constraining FEA model. ResultsThe linear and non-linear DEA model reproduced a mean articular contact stress within 0.36 MPa and 0.39 MPa of the FEA calculated stress, respectively. With respect to the ligamentous validation, the DEA ligament-balancing algorithm could reproduce the position of the distal fibula within the ankle mortise to within 0.97 mm of the experimental observed distal fibula. When combining the ligament-constraining and contact stress algorithm, DEA was able to reproduce a mean articular contact stress to within 0.50 MPa of the FEA calculated contact stress. ConclusionThe DEA framework presented herein offers a computationally efficient alternative to FEA for the prediction of contact stress in the ankle joint, manifesting its potential to enhance the mechanical understanding of articular ankle pathologies on both a patient-specific and population-wide level. The novelty of this model lies in its personalized nature, inclusion of the distal tibiofibular joint and the use of non-linear ligament balancing to maintain the physiological ankle joint articulation.

Influences of altering footstrike pattern and cadence on lower extremity joint coordination and variability among runners with patellofemoral pain.

Patellofemoral pain (PFP) is a common overuse injury among runners. It is not only a hindrance to the runner's training, but also to the runner's quality of life. PFP runners may strategize different running strategies to reduce patellofemoral joint stress, release pain, and improve function. This study aimed to determine the changes in joint coordination and variability under combinations of foot strike pattern and cadence for runners with patellofemoral pain. Twenty male runners with PFP performed six running strategies which were two strike patterns named forefoot (FFS) and rearfoot (RFS) accompanied by three running cadences named slow10%, normal, and fast10%. A modified vector coding technique and circular statistics were respectively used to identify the coordination pattern and variability between hip sagittal-knee frontal (HsKf), hip sagittal-knee sagittal (HsKs) and knee transverse-ankle frontal (KtAf) during stance phase. Coordination patterns which were conformed with anatomical motion pattern was classified as mechanically sound, and the distribution frequency of each coordination pattern was quantified. Switching to FFS, the HsKf couples (p < 0.001, ES = 1.34) and the HsKs couples (p = 0.001, ES = 0.82) displayed significantly greater frequency in mechanically unsound coordination pattern during the initial stance phase. The effect of increasing running cadence on RFS displayed significantly greater frequency in mechanically unsound hip dominancy (p = 0.042, ES = 0.65) and knee dominancy (p = 0.05, ES = 0.70) coordination patterns for HsKf couples as well as for HsKs couples (p = 0.023, ES = 0.86) during the initial stance phase. Combined with FFS and fast10% cadence, HsKs couples showed more hip-dominated mechanical sound coordination pattern (p = 0.002, ES = 1.25). Further, altering footstrike pattern and cadence failed to change the coordination variability. Changing running cadence (± 10%) combined with transfer strike pattern from RFS to FFS could not increase the distribution frequency in mechanically sound coordination patterns and change coordination variability for PFP runners.

Coupled thermal-hydro-mechanical modeling on characteristics of excavation damage zone around deep tunnels crossing a major fault

An understanding of excavation damage zone (EDZ) is critical in safe construction of underground openings, but conventional continuum-based numerical methods such as finite element method or finite difference method have limitations in simulating crack development under coupled thermal-hydro-mechanical (THM) conditions. In this study, a numerical method of predicting EDZ subjected to coupled THM conditions is developed based on discrete element method (DEM), which can simulate propagation of newly formed cracks by adding fictitious joints. A physical model of a high temperature tunnel filled with pressurized water is first used to verify the accuracy and efficiency of the developed numerical method. Based on the case study of the Baoling Mountain tunnel of the Sichuan-Tibet railway, the effects of coupled THM conditions on characteristics of EDZ are investigated. The results show that the two EDZ indices of volume of plastic zones per length and area of cracks per length increase from M-only to THM scenarios. In addition, the shear displacements of the fault in the roof and floor of the tunnel also increase from M-only to THM scenarios. The increasing EDZ size and fault displacement in THM scenario is attributed to the higher ambient rock stress and water pressure in the fictitious joints and the fault. In high temperature regions, thermal stress increases the maximum principal stresses and induces rock damage. Effect of fault dip angle on characteristics of EDZ is also discussed.

Kinematic study of the overall unloading brace for the knee

ObjectiveTraditional knee braces unloading forces primarily from a single compartment are insufficient for patients with knee injuries or knee osteoarthritis (KOA) involving multiple compartments. We investigated how knee kinematics were altered by an overall unloading brace (OUB) designed to unload both the medial and lateral tibiofemoral (TF) compartments simultaneously during dynamic movement. MethodsGait analysis was performed on 32 adults with normal knee alignment and no history of knee disease. Three-dimensional (3D) knee kinematic data collected during treadmill walking (3 km/h) and jogging (5 km/h) with an optical motion capture system were compared with versus without the OUB. ResultsIn the stance phase, wearing the OUB, versus not wearing it, increased the proximal-distal translational range of motion (ROM) of the knee by 4.04 mm (Effect size, ES = 0.97) during walking and by 3.43 mm (ES = 0.97) during jogging, decreased abduction-adduction rotational ROM by 3.09°(ES = 1.05) during walking and by 2.88°(ES = 1.50) during jogging, and decreased internal-external rotation by 2.14°(ES = 0.81) during walking and by 4.66°(ES = 1.61) during jogging. In the swing phase, the OUB increased proximal-distal translational ROM by 12.64 mm (ES = 1.31) during walking and by 9.23 mm (ES = 0.92) during jogging, decreased abduction-adduction rotational ROM by 2.83°(ES = 0.54) during walking and by 3.37°(ES = 0.67) during jogging, and decreased internal-external rotational ROM by 2.71°(ES = 0.68) during jogging. ConclusionsOUB use increased proximal-distal translation while reducing abduction-adduction rotation. This effect may increase the joint gap of the tibiofemoral joint, thereby reducing joint stress, and may contribute to disease rehabilitation in the knee of clinical orthopedics, rehabilitation, and sports medicine fields. However, additional studies are needed to assess the range of possible clinical and prophylactic benefits of OUB.

Effect of Diamond Burnishing on the Properties of FSW Joints of EN AW-2024 Aluminum Alloys

The article presents the results of an analysis of the surface roughness parameters, microhardness, and the stresses of the surface layer ofFSW butt joints subjected to the burnishing process with a diamond tip. This can be useful in selecting the optimal parameters of the burnishing process, ensuring the best properties of the surface layer of the FSW joint. Burnishing force and feed rate influence were analyzed according to the two-factor three-level full factorial statistical completed plan PS/DC 32. The tested material was 2024-T3 aluminum alloy sheets with a thickness of 2 mm. The results show that burnishing significantly reduced the surface roughness from Sa = 6.46 μm to Sa in the range of 0.33 μm–1.7 μm. This treatment provides high compressive residual stresses σx from −86 to −130 MPa and σy from −158 to −242 MPa. Microhardness increased from 84.19% to 174.53% compared to butt joints. Based on the obtained results, multi-criteria optimization was carried out. This optimization allows us to obtain a compromise solution ensuring compressive stresses in the surface layer (σx=−123 MPa and σy=−202 MPa) and microhardness HV=362.56 mm/mm2 with the roughness of the weld surface Sa = 0.28 µm, Sku = 3.93 and Spc = 35.88 1/mm.

Hesperidin Methyl Chalcone Reduces the Arthritis Caused by TiO2 in Mice: Targeting Inflammation, Oxidative Stress, Cytokine Production, and Nociceptor Sensory Neuron Activation.

Arthroplasty is an orthopedic surgical procedure that replaces a dysfunctional joint by an orthopedic prosthesis, thereby restoring joint function. Upon the use of the joint prosthesis, a wearing process begins, which releases components such as titanium dioxide (TiO2) that trigger an immune response in the periprosthetic tissue, leading to arthritis, arthroplasty failure, and the need for revision. Flavonoids belong to a class of natural polyphenolic compounds that possess antioxidant and anti-inflammatory activities. Hesperidin methyl chalcone's (HMC) analgesic, anti-inflammatory, and antioxidant effects have been investigated in some models, but its activity against the arthritis caused by prosthesis-wearing molecules, such as TiO2, has not been investigated. Mice were treated with HMC (100 mg/kg, intraperitoneally (i.p.)) 24 h after intra-articular injection of 3 mg/joint of TiO2, which was used to induce chronic arthritis. HMC inhibited mechanical hyperalgesia, thermal hyperalgesia, joint edema, leukocyte recruitment, and oxidative stress in the knee joint (alterations in gp91phox, GSH, superoxide anion, and lipid peroxidation) and in recruited leukocytes (total reactive oxygen species and GSH); reduced patellar proteoglycan degradation; and decreased pro-inflammatory cytokine production. HMC also reduced the activation of nociceptor-sensory TRPV1+ and TRPA1+ neurons. These effects occurred without renal, hepatic, or gastric damage. Thus, HMC reduces arthritis triggered by TiO2, a component released upon wearing of prosthesis.

Optimization and fatigue life analysis of flexible joint

–Taking the solid rocket motor flexible joint as the object, in order to meet its lightweight design and fatigue performance requirements, improve the overall performance of the nozzle. Using nonlinear finite element numerical calculation method. Taking the radial size of the joint as a design variable. Establish a flexible joint optimization model based on design variables, constraints and objective functions. Using response surface screening optimization algorithm, obtain the optimized structure of the variable cross-section flexible joint. Calculation and analysis of joint bearing performance. After optimization, the stress of the variable cross-section flexible joint meet the design requirements, and the mass is reduced by 18.81%. Based on the principle of crack propagation, the fatigue life of the joint is calculated and analyzed by using the numerical calculation method of strain fatigue, meet the design requirements.

Phenotypic and transcriptomic shifts in roots and leaves of rice under the joint stress from microplastic and arsenic

Co-contamination of soil from microplastics (MP) and arsenic (As) is becoming more prevalent, posing a severe threat to agricultural productivity. However, how this joint pollution affects crop growth needs to be better understood. To assess this, we investigated the transcriptomic and phenotypic patterns of rice (Oryza sativa) to MP, As, and their mixtures. The results revealed that, compared to As, MP had much less impact on rice growth, while the MP-As mixture decreased rice’s aboveground biomass and altered As’s biodistribution in rice tissues. Transcriptome further corroborated this pattern: 13 (294), 4195 (1842), and 3112 (2063) genes differentially regulated in response to MP, As, and their mixtures were observed in root (leaf) tissues, respectively. The joint application of MP and As produced a synergistic effect on crucial metabolic processes, such as carbohydrate, carboxylic acid, oxoacid, organic acid, amino acid, and tetrapyrrole metabolism. Moreover, we found that the joint stress reprogrammed the expression of hub genes encoding photosynthetic enzymes, protein kinases, and transcription factors, which likely reflect a transcript-driven tradeoff strategy between rice growth and defense. Together, these results strongly indicate that MP aggravated the As-induced toxicity in rice plants, which may impact the crop’s acclimation to other abiotic field environments.

Optimization and experimental research on treelike joints based on generative design and powder bed fusion

Optimization and intelligent construction are of particular interest and important to improve the traditional design and manufacturing methods of cast steel joints. The optimal design, intelligent construction, and experimental research of treelike joints are conducted is this study based on generative design and laser power bed fusion (L-PBF) technology. First, the principle of generative design is comprehensively discussed in accordance of the Audze space-filling criteria. This method is applied to the optimal design of the treelike cast steel joint for Jinming Campus Museum of Henan University. Second, static behaviors of the generative design joints are compared with those of other joints obtained via parametric design through ANSYS version 2022R1 (64-bit) software. Finally, instead of traditional casting, all joints are produced using the L-PBF technology, and the manufactured 316L stainless steel joints are subjected to experimental research and finite element analysis. Results showed the minimum mass, optimal static behaviors, and evenly distributed stress of the generative design joint, thereby indicating that the generative design can effectively optimize treelike cast steel joints. The failure mode of 316Lstainless steel joints obtained via the L-PBF technology is similar to that of traditional cast steel joints but with higher yield load and ultimate bearing capacity. Therefore, employing the generative design and L-PBF technology in the optimization and intelligent construction of cast steel joints is effective and feasible.

Bending Strength of Connection Joints of Prestressed Reinforced Concrete Pipe Piles

The connection joint of prestressed concrete pipe piles is a typical steel–concrete structure, and its bending strength has evolved into a critical factor affecting the safety of supporting structures in underground engineering. Based on full-scale bending tests of five specimens of large-diameter prestressed reinforced concrete (PRC) pipe piles and connection joints, as well as the corresponding finite element numerical simulation, the bending bearing and deformation characteristics of connection joints of PRC pipe piles were analyzed, together with the effects of concrete strength, precompression stress, and connection mode of joints. The results showed that the crack resistance of the welded joint of PRC pipe piles was equivalent to that of the pipe pile shaft, but the ultimate bending moment of the joint was about 58–87% of that of the pile shaft. The bending failure mode of the pipe pile joint was mainly manifested in the end plate yielding into a drum shape, with the tension side of the pile hoop and the end plate clearly separated from the pipe pile, and crushed concrete at the upper edge of the pile hoop. The bending strength of the joint can be improved by increasing the bonding strength between the end plates of the joint or embedding Rachel reinforcement in concrete. In addition, synchronously increasing the strength grade and reinforcement ratio of concrete or strengthening the precompression stress of concrete are favorable measures.

Numerical Analysis of the Stress Distribution and Concentration Factors of the Tool Joint of the Directional Drill Pipe

With the wide application of directional drilling technology in coal mine predraining boreholes, the failure problem of the tool joint of the directional drill pipe has become one of the main factors restricting the drilling efficiency. The main reason for the failure problem of the tool joint of the directional drill pipe is the stress concentration. The stress test rig for the tool joint of the directional drill pipe is designed based on the resistance strain measurement method, and the stress of the tool joint of the directional drill pipe is tested. The tool joint’s 3D finite element model was established based on nonlinear contact theory. The experiment verified the accuracy of this model. The stress distribution of the tool joint of the directional drill pipe was obtained. The research shows that the stress of the tool joint of the directional drill pipe is concentrated at the root between the third and the fourth turn of the engaged thread. The work presented in this study is a reliable guide to the design and field use of the tool joint of the directional drill pipe.

FEA AND EXPERIMENTAL INVESTIGATION OF PROSTHETIC KNEE JOINT

This study has taught us how to assess the knee joint using a range of variables, yielding diverse outcomes. Furthermore, it elucidates the importance of the knee joint's stress capacity and the generation of various loading scenarios through these input variables. The primary focus of the research is on static analyses, enabling us to gain insight into knee capacity and the necessary stress conditions, which are vital for our understanding. Additionally, the study delves into the examination of kinematics within the experiment. The findings of the study indicate that mechanical testing methods are employed to assess the current state of the knee implant market.

Effect of change in patellofemoral joint contact area by the decrease in vastus medialis muscle activation on joint stress

Purpose Patellofemoral pain syndrome is a common orthopedic trauma among runners. It is unclear whether patellofemoral joint stress (PFJS) is the highest (or lowest) when the knee joint flexion angle and extension moment are in combination under the condition that vastus medialis (VM) activation decreases. This study aimed to investigate the effects of changes in the PFJ contact area by decreasing the activation of the VM muscle on PFJS. Methods A PFJ sagittal model was used to quantify PFJ reaction force and PFJS. The PFJ model and mathematical modelling procedure were used to quantify PFJS based on previous studies. The simulation ranges were set to knee joint flexion angles of 10–45 degrees and extension moments of 0–240 Nm. PFJS was calculated for the normal condition (NC) and decrease condition (DC) in VM activation. Results When the knee joint angle and knee joint moment were at the maximum, the PFJS showed the maximum value under both conditions (NC; 14.9 N/cm2, DC; 16.4 N/cm2). PFJS was found to be higher in DC than that in NC for all simulation ranges. Conclusions Decreased VM activation may be involved in the mechanism of patellofemoral pain syndrome. In addition, the results of this study provide evidence that clinicians can enhance VM to relieve pain in patients with patellofemoral pain syndrome.

Residual Stress and Fracture Toughness Study in A516 Gr70 Steel Joints Welded and Repaired by Arc Processes

Residual Stress and Fracture Toughness Study in A516 Gr70 Steel Joints Welded and Repaired by Arc Processes

A survey on classification methodologies utilized for classifying the knee joint disorder levels using vibroarthrographic signals

The largest as well as complicated joint in the human body is knee joint. A minor pathology in human knee can lead to major discomfort to a person. The pathology may be from a simple stress in knee joints to the higher effective levels of pathology that includes osteoarthritis (OA), chondromalacia patella (CMP) and so on. Hence prediction as well as classification of knee joint pathology plays a vital role for computational medical diagnosis. Pathology identification can be categorized in to two levels invasive and non – invasive methodologies. Invasive are purely medical as well as painful process which are less preferred for predictions. Noninvasive are clinical and computational ones that includes X-Rays, Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Vibroarthography (VAG) etc. This paper compares various classification methodologies utilized by Vibroarthographic (VAG) signal based knee joint disorder level identification and performs a binary classification of data samples as a survey.

Numerical Analysis of 3D CSP MEMS Under Thermal Cycle-Impact Coupled Multiphysics Loads

In this paper, reliability analysis of 3D CSP MEMS and IC under thermal cycle-impact coupled multi-physics loads was investigated. COMSOL Multiphysics, a finite element software, was used to analyze our device’s mechanical behavior under a -55°C/125 °C thermal cycling and 1500G@1ms with half-sine pulse impact coupled load. In details, MEMS chip was bonded on a silicon interposer by solder balls and an application specific integrated circuit (ASIC). Thermal stress of single solder joint, whole device, and the simulation of device reliability under different magnitudes and forms of mechanical shock were carried out, respectively. Combining the effects of impact and thermal stress loads, we hope to find out the failure modes of interconnect structures for future design including solder joints and whole device. The stress distribution and deformation of the overall device will be carried out for layout optimization of interconnect structures.

Effect of abnormal occlusal contact on temporomandibular joint

Occlusion, temporomandibular joint and masticatory muscle are in a functional system, which cooperate and influence each other. When any one of these elements is abnormal, it will affect the function of other elements. The normal occlusal relationship is the convex-concave relationship of apical fossa contact, and the masticatory movement trajectory is teardrop-like, which is helpful to promote the normal mandibular functional movement. The abnormal occlusal contact relationship changes the convex-concave relationship of apical fossa contact into convex relationship, which will form abnormal masticatory movement trajectory, and may even cause abnormal movement and stress of temporomandibular joint and abnormal contractile activity of masticatory muscle. The longer the duration of this abnormal occlusal relationship, the greater the damage to bone and soft tissue. scissors bite, openbite and crossbite are common occlusal abnormalities in clinic, so this article will focus on the effects of these three abnormal occlusal contacts on the temporomandibular joint.