Joint Stress Research Articles

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.

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.

Reliability analysis for bond stress of precast panel joints

Reliability analysis for bond stress of precast panel joints

Reliability analysis for bond stress of precast panel joints

Reliability analysis for bond stress of precast panel joints

Experimental Methods for Studying the Contact Mechanics of Joints.

Biomechanics researchers often experimentally measure static or fluctuating dynamic contact forces, areas, and stresses at the interface of natural and artificial joints, including the shoulders, elbows, hips, and knees. This information helps explain joint contact mechanics, as well as mechanisms that may contribute to disease, damage, and degradation. Currently, the most common in vitro experimental technique involves a thin pressure-sensitive film inserted into the joint space; but, the film's finite thickness disturbs the joint's ordinary articulation. Similarly, the most common in vivo experimental technique uses video recording of 3D limb motion combined with dynamic analysis of a 3D link-segment model to calculate joint contact force, but this does not provide joint contact area or stress distribution. Moreover, many researchers may be unaware of older or newer alternative techniques that may be more suitable for their particular research application. Thus, this article surveys over 50 years of English-language scientific literature in order to (a) describe the basic working principles, advantages, and disadvantages of each technique, (b) examine the trends among the studies and methods, and (c) make recommendations for future directions. This article will hopefully inform biomechanics investigators about various in vitro and in vivo experimental methods for studying the contact mechanics of joints.

Correlation between Temporomandibular Joint Disorders, Sleep Quality and Stress among Dental Students: A Cross-sectional Study

Introduction: Dental students are subjected to high levels of stress during their academic performance. The quality of sleep could also be affected in those with increased stress levels. Stress and sleep quality could be considered as risk factors in Temporomandibular Joint Disorders (TMD). Identification of the risk factors in TMD at the initial stages can lead to minimising the long term effects. Aim: To investigate the relationship between TMD symptoms, sleep quality and stress among dental students. Materials and Methods: A cross-sectional questionnairebased survey was conducted in the Department of Oral Medicine and Radiology, Sinhgad Dental College and Hospital, Pune, Maharashtra, India, from November 2021 to December 2021 among 255 dental students. Fonseca Anamnestic Index (FAI) questionnaire was used for evaluation of TMD, while Perceived Stress Scale (PSS) and Pittsburgh Sleep Quality Index (PSQI) were used to assess stress scores and sleep quality, respectively. The students were surveyed to categorise them, if they were showing any symptoms of mild, moderate or severe TMD. Similarly the sleep quality and stress scores were assessed. The relationship between TMD with stress and sleep quality was also evaluated. Data analysis was done using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) version 26.0. Comparison of frequencies of scores of PSS, PSQI and FAI within groups was done using Chi-square test. Bivariate correlation between PSS/PSQI, PSS/ FAI ad FAI/PSQI was assessed using correlation coefficient. Results: Out of 255 participants, 182 were females and 73 were males. It was observed that 221 (86.7%) students reported moderate stress levels, 21 (8.2%) students showed mild and 13 (5.1%) subjects showed high stress levels. Temporomandibular symptoms were reported as mild, moderate and severe in 130 (51%), 21 (8.2%) and 9 (3.5%) students, respectively. A total of 229 (89.8%) students showed poor sleep quality and 26 (10.2%) students showed good sleep quality. Moderate stress was correlated with poor sleep quality and mild TMD. Conclusion: The stress levels were significantly correlated with sleep quality and TMD symptoms. Thus, increased stress and poor sleep may be considered as risk factors of TMD. However, longitudinal studies in large samples are required to determine the cause and effect relationships between sleep quality, stress levels and TMD.

Board-Level Drop Impact Reliability Analysis of Dual-Side Molding System-in- Package (SiP) Modules

System-in-package (SiP) modules are widely used in portable electronics such as Internet of Things (IoT) devices and mobile consumer equipment since they integrate multiple components in a single package and thus facilitate device miniaturization. An advanced packaging technology referred to as dual-side molding (DSM) has recently been proposed as a means of achieving even smaller form factors and lower cost solutions. However, shrinking the package size reduces the solder joint connection area between the SiP module and the printed circuit board (PCB). Consequently, the board-level drop reliability may be severely impaired. Accordingly, the present study utilizes a numerical model to investigate the board-level solder joint reliability of a DSM SiP package in drop impact tests performed in accordance with the Joint Electron Device Engineering Council (JEDEC) standard. The validity of the numerical model combined with a full-factorial design method is then employed to examine the effects of the main design parameters of the DSM SiP package on the reliability of the solder joints in the drop impact test. Overall, the present results show that a higher EMC coverage of the solder ball joints yields a significant improvement in the solder joint reliability. In addition, a larger solder joint volume is beneficial in reducing the solder joint stress by absorbing a greater proportion of the impact load and energy produced in the drop impact event.

Finite element analysis to predict the cyclic performance of GFRP-RC exterior joints with diagonal bars

This paper presents a finite element modeling (FEM) approach to predict the cyclic response of glass fiber-reinforced polymer (GFRP) reinforced concrete (RC) exterior beam-column joints with different joint details. Four GFRP-RC exterior beam-column joints detailed with U or L-shaped anchorages at the end of the longitudinal bars of the beam, horizontal stirrups and additional diagonal bars (Z or U-shaped) at the joint region were modeled and analyzed under reversed cyclic loading. The FEM cyclic behavior in terms of load-drift ratio, cracking patterns, joint shear stress and strain evolutions were compared with the experimental behaviors. The FEM predicted load-drift ratio response, cracking patterns and dissipated energy showed good correlations with the experimental results. A parametric study was conducted to evaluate the influence of compressive strength of concrete, column axial load ratio and size of the additional diagonal bar on the performance of the GFRP-RC joints. It was found that an increase in the column axial load significantly degraded the performance in terms of strength, maximum joint shear stress and ductility of the GFRP-RC joints. Also, GFRP-RC joints with additional U-bars were able to resist higher joint shear stress and drift ratio than GFRP-RC joints with additional Z-bars, respectively.