Cross Joint Research Articles

Mechanical behaviour of bridge expansion joint interfaces filled with novel polyurethane-modified asphalt

The use of Asphalt Plug Joints (APJs) in bridge construction has rapidly expanded due to their distinct advantages in driving comfort, shock absorption, noise reduction, and maintenance ease. However, prolonged exposure to vehicular loads and environmental factors renders this expansion joint susceptible to interface effects and stress concentration, leading to damage, particularly at the interface layers between the expansion joint pavement and the expansion joint-cross joint plate contact areas. To address issues such as stress concentration, this study proposes a polyurethane-modified asphalt concrete mixture as the joint filling material. Pull-out and inclined shear tests are used to identify a bonding agent with superior adhesive properties. Additionally, a finite element model of pull-out specimens containing bilinear cohesive elements is established to simulate the cohesive damage process of the interface layers. Through parameter design analysis, the study examines the influence of individual parameter variations on interface damage behavior, obtaining comprehensive simulated analysis data on interface crack resistance performance. Based on interface test data, a bilinear cohesive force model and a viscoelastic material model of the asphalt concrete mixture are employed to establish a scaled-down model of the improved geometry design of the new APJ. This model simulates the interface mechanical characteristics of APJs under temperature effects and vehicle loads. The results demonstrate that the bilinear cohesive force model effectively simulates the nonlinear behavior of interface bonding slip. Furthermore, the use of SZ interface bonding agents and improvements in cross joint plate form can effectively mitigate issues such as uneven settlement and low-temperature cracking.

Nematocida displodere mechanosensitive ion channel of small conductance 2 assembles into a unique 6-channel super-structure in vitro.

Mechanosensitive ion channels play an essential role in reacting to environmental signals and sustaining cell integrity by facilitating ion flux across membranes. For obligate intracellular pathogens like microsporidia, adapting to changes in the host environment is crucial for survival and propagation. Despite representing a eukaryote of extreme genome reduction, microsporidia have expanded the gene family of mechanosensitive ion channels of small conductance (mscS) through repeated gene duplication and horizontal gene transfer. All microsporidian genomes characterized to date contain mscS genes of both eukaryotic and bacterial origin. Here, we investigated the cryo-electron microscopy structure of the bacterially derived mechanosensitive ion channel of small conductance 2 (MscS2) from Nematocida displodere, an intracellular pathogen of Caenorhabditis elegans. MscS2 is the most compact MscS-like channel known and assembles into a unique superstructure in vitro with six heptameric MscS2 channels. Individual MscS2 channels are oriented in a heterogeneous manner to one another, resembling an asymmetric, flexible six-way cross joint. Finally, we show that microsporidian MscS2 still forms a heptameric membrane channel, however the extreme compaction suggests a potential new function of this MscS-like protein.

Motion Branch Transformation of 3(Rc)PU Parallel Mechanism with Reconfigurable Joint and Kinematic Performance Index

A novel 3(Rc)PU parallel mechanism based on the reconfigurable circular groove cross joint (Rc joint) is proposed. The motion branch transformation relationship and constraint performance evaluation method for the mechanism are studied. According to constrained screw analysis, the (Rc)PU limb provides a constraint couple to the moving platform in one motion mode and no constraint to the platform in another motion mode. According to the two configurations of the limb, the 3(Rc)PU mechanism has four different motion branches, namely 3T, 1R3T, 2R3T, and 3R3T. Based on the input selection principle, the input selection scheme of the 3(Rc)PU mechanism is determined, and it is concluded that, to achieve stable motion, at least two input drive pairs need to be applied on each limb. A unified kinematic model with four motion branches is established, and the geometric constraint equations of the 3(Rc)PU parallel mechanism are derived. After selecting the input actuated joints, the local minimization transmission index (LMTI) of the reconfigurable mechanism under different motion branches is established to evaluate the motion/force transmission performance of the reconfigurable mechanism under different motion branches. The conclusion shows that the LMTI values satisfy the corresponding constraint conditions, and the 3(Rc)PU parallel mechanism has good motion/force transmission performance.

Localized scleroderma

Localized scleroderma (LS), also called circumscribed scleroderma or morphea, comprises aheterogeneous group of diseases that can be classified into four subtypes: limited, linear, generalized, and mixed LS. All manifestations are primarily due to chronic progressive fibrosis of the skin or structures close to the skin. Involvement of internal organs or the transition to systemic sclerosis is excluded by definition. Adistinction is made between forms that primarily affect the skin (up to the dermis) or that severely involve subcutaneous fat tissue, muscle fascia or muscles. Adetailed examination is required for clinical diagnosis. In order to improve comparability of findings, photo documentation and the use of clinical scores should be carried out. For superficial subtypes the use of topical glucocorticosteroids, calcineurin inhibitors or phototherapy is initially recommended, whereas for severe forms with deep involvement or overall therapy refractoriness, the diagnosis should first be expanded and systemic therapy initiated at an early stage. Especially, in cross joint or extremity-dominant forms of linear LS or in cases with head and neck involvement, such as en coup de sabre, Parry-Romberg syndrome and other subtypes with aprominent musculoskeletal affection, an MRI examination should be arranged. Depending on location, an ophthalmological, neurological, orthodontic, rheumatological or orthopedic consultation may be necessary. For systemic therapy, methotrexate alone or in combination with systemic glucocorticosteroids as pulse therapy is recommended as first-line treatment.

Fatigue strength of cruciform joints with weld imperfections: A comprehensive numerical study

The paper presents an investigation into the fatigue resistance of load-carrying cruciform joints that exhibit weld imperfections. To accomplish this, a finite-element model of the joint is validated by a comparison to experimental investigations. The model includes both a global and a submodel that integrates the effective notch stress concept into its design. This enables the simulation of various types of weld imperfections, such as lack of penetration, lack of root fusion, undercut, excessive convexity, incorrect weld toe, excessive asymmetry of fillet welds and linear misalignment, to assess their impact on the fatigue strength of the cruciform joint. The analysis reveals that these imperfections lead to an increase in stress at the notches of the cruciform joint, which can be characterized as a function of the joint's geometrical properties. Global geometry influences on the fatigue strength of different cruciform join geometries can be regarded independently from the influence of the weld imperfections that is given by stress concentration factors. The normalised stress concentration factor enables a comparison between imperfection influences and shows, that the notch-softer design with full penetration welding at the cruciform joint is in a relative relation more strongly influenced by imperfections than the design with fillet welds. Also, the undercut represents the imperfection with the strongest effect in a relative relation within the sizes considered.Being able to evaluate the fatigue strength values of steel components with weld imperfections eliminates the need for costly repairs and new fabrications, which would otherwise result in a loss of resources and economic efficiency.

Flexural study on U-shaped steel–concrete composite beam cross joints with L-shaped connection longitudinal transition components

The paper focuses on the U-shaped steel–concrete composite bottom beam cross joints of U-shaped Steel-concrete Composite Open-web Sandwich Plate (USCOSP), presenting a new type of cross joints transmitting the internal force of steel web by L-shaped connection Longitudinal Transition Component (LLTC). LLTC consists of sleeves, L-shaped connection plates and threaded rebars installed on the steel web using sleeves and L-shaped connection plates. Compared with the conventional cross joints which transmit internal force of steel web by Welded Longitudinal Transition Rebar (WLTR), the LLTC cross joints transfer eccentric internal force within the steel web. Through simple-point loading experiments with simply-supported at four ends, the research experimentally investigated the flexural behavior of the WLTR cross joints and the LLTC cross joints. The five specimens were varied to differ in the type of longitudinal transition components, the diameter of WLTR, the number of threaded rebars of LLTC and the strength grades of threaded rebars of LLTC. Experimental results showed that the failure mode of U-shaped steel–concrete cross joint was the buckling of steel web, the buckling of top longitudinal rebar and crush on the concrete under compression near the central region. The LLTC cross joints experienced higher load capacity and better ductility than WLTR cross joints because of little steel web buckling. The ultimate load capacity calculated according to JGJ 138–2016 and the deflection in the elastic stage calculated according to the displacement method agree well with the experiment results.

Using 3D‐scanners and finite element method to assess the fatigue life of welded joints based on the actual geometry of seam welds: realistic modelling of notches at the weld toe

AbstractTo predict the service life of welded joints, the seam welds of samples (cross joint, K‐seam, sheet thickness 15 mm and a laser‐welded butt joint, sheet thickness 6 mm, both made of steel quality S 355) are recorded using a 3D scanner. The data obtained in this way is processed and transferred to a finite element method program. The meshing of the weld seams is very detailed. A finite‐element‐method stress calculation is then carried out. The real samples are tested in a fatigue test up to the point of cracking. The results from calculation and test are then compared. A possible crack location can be predicted very well using the finite element method results. The cracks in the real test are always in the area of very high or often the absolute highest calculated stresses. A prediction of the service life in the fatigue test is possible with a certain scatter – close to the usual scatter for welded joints. Based on the results of 19 samples, a fatigue class for local stress (based on the real geometry) of FAT 300 can be preliminary estimated for the cross‐joint specimens. Definition according to the specifications of the International Institute of Welding (FAT at 2 mio. cycles, survival probability 97.7 %).

Investigating the effect of residual stresses and distortion of laser welded joints for automobile chassis and optimizing weld parameters using random forest based grey wolf optimizer

The present investigation analyses the selection of the right welding method and joint and advanced testing methods (NDT) for highly durable automotive frames. Moreover, the present investigation analysis suggests the best machine learning (ML) algorithm for selecting the best weld method and optimal solution. The experiment was performed based on the response surface methodology (RSM) based design of the experimental approach. As a result, laser beam welding (LBM) and cross joint are the significant weld methods for automotive frames. The proposed ML algorithm successfully optimized the LBM input parameters as laser power = 1277 W, welding speed (WS) = 32.2 mm/s, focal point: 1 mm and working angle = 0.14 Rad with an average error of approximately 0.033. Based on the results, the optimum output weld parameters are bead width = 4322.7 µm, penetration depth (PD) = 3157.9 µm, total strain = 0.0098 mm/mm and residual stress = 645.2340 MPa, respectively.

Diffusion of point source pollution at the cross joint

Abstract The cross joint is one of the standard connection types for urban water supply pipelines. A pipeline containing cross joints was taken as the research object using NaCl as the tracer. The turbulent mixing characteristics of water and pollutants at the cross joints and pollutant migration and diffusion were studied and analysed by numerical analysis and experimental measurement. The primary purpose is to check the comprehensive influence of the six factors of pipe diameter, inlet flow ratio, outlet flow ratio, location of damage point, flow of brine, and density of brine on the turbulent mixing of water and brine in the pipeline. The coefficient of variation is used as an evaluation index to evaluate the mixing in the pipeline, and the effective mixing length LEML is used to quantify the uniform mixing position of brine in the pipeline. The results show that the inlet flow ratio, outlet flow ratio, and pipe diameter significantly affect LEML in the east outlet of the cross joint. Outlet flow ratio and pipe diameter significantly affect LEML in the cross joint's south outlet direction. In addition, the dimensionless relationship equation representing LEML is fitted through dimensional analysis.

Digital image processing-based automatic detection algorithm of cross joint trace and its application in mining roadway excavation practice

This paper proposes a digital image processing-based detection algorithm for cross joint traces of coal roadway heading face. Initially, the acquired images were preprocessed, i.e., adaptive correction was conducted for non-uniform illumination images based on the 2D gamma function. The edge detection algorithm was then applied to extract the edges of the structural plane, followed by the filtration of the non-structural plane noises. Moreover, the Hough transform algorithm was applied to extract the linear edges; finally, the edges were locally connected in accordance with the angle and distance criteria. The experimental results show that this algorithm can be used to reduce the noise caused by non-uniform illumination and avoid the mutual interference of multi-scale edges, so as to effectively extract the traces of the cross joint. Furthermore, Q-system and rock mass rating (RMR ) , were applied to conduct a quantitative evaluation on the stand-up time of unsupported roof in the four test images. The Q-system quality scores are 26.7, 43.3, 3.1, and 6.7, and the RMR quality scores are 56.84, 58.73, 48.42, and 51.42, respectively. The stand-up time of unsupported roofs with a span of 4.6 m are 30, 36, 7.7 and 14 d, respectively.

Generative Design and Integrated 3D Printing Manufacture of Cross Joints.

The integrated process of design and fabrication is invariably of particular interest and important to improve the quality and reduce the production cycle for structural joints, which are key components for connecting members and transferring loads in structural systems. In this work, using the generative design method, a pioneering idea was successfully realized to attain a reasonable configuration of the cross joints, which was then consecutively manufactured using 3D printing technology. Firstly, the initial model and generation conditions of a cross joint were constructed by the machine learning-based generative design algorithm, and hundreds of models were automatically generated. Then, based on the design objective and cost index of the cross joint, three representative joints were selected for further numerical analysis to verify the advantages of generative design. Finally, 3D printing was utilized to produce generative joints; the influences of printing parameters on the quality of 3D printing are further discussed in this paper. The results show that the cross joints from the generative design method have varied and innovative configurations and the best static behaviors. 3D printing technology can enhance the accuracy of cross joint fabrication. It is viable to utilize the integrated process of generative design and 3D printing to design and manufacture cross joints.

Relationship between Maxillary Sinus Hypoplasia and Maxillary Occlusal Cant: A Cone Beam CT Study

Introduction. Maxillary sinus hypoplasia (MSH) has been reported to cause a cant in the orbital plane. No similar reports exist about the possible impact on the maxilla. The aim of this study was to assess if MSH is associated with maxillary occlusal plane (MOP) cant and if dental or mandibular factors influenced the existence of the MOP cant. Methods. 80 cone beam CT images of subjects with MSH were analyzed for the type of MSH, degree of MOP cant, open or cross bite, mandibular asymmetry, and degenerative joint disease of the temporomandibular joints. The subjects were compared with a control group matched by age and gender. Results. The degree of MOP cant (range 0–5.1°) was not statistically significantly different in unilateral vs. bilateral MSH or between the different types of MSH. The frequency of open bite, crossbite, mandibular asymmetry, or degenerative joint disease in unilateral vs. bilateral MSH or between the different types of MSH was not statistically significantly different. Between the case and control, there was no statistically significant difference in the degree of MOP cant ( 1.3 ± 1.1 ° vs. 1.1 ± 0.9 ° , respectively) or frequency of dental and mandibular factors. There was low positive linear correlation between MOP cant and mandibular symmetry in MSH subjects (Spearman’s rho = 0.23 ) and controls (Spearman’s rho = 0.18 7). Conclusions. The data suggests a view of the alveolar bone as the adaptable skeletal unit to ensure and bridge the functionality between the nasomaxillary complex and TMJ system–two systems with very different function, and therefore largely independent “matrix units.”

The Effect of Discontinuity Orientation and Thickness of the Weathered Layer on the Stability of Lesser Himalayan Rock Slope

Abstract The effect of discontinuity orientations and thickness of the weathered layer in the stability of jointed phyllite rock slopes of the Lesser Himalayan region was examined in this study. Numerical simulation was performed using the Rocscience RS2 V9 finite element software package. The performance of the slope was assessed for varying slope height, slope angle, weathered layer thickness, and orientation of the main joint and the cross joint set. The results indicate that the stability of rock slope depends on the relative orientation and distribution of the contained joint sets and the thickness of the weathered layer. Based on numerical simulation, the order of percentage reduction of a factor of safety (FOS) for the critical combination of joint sets has been identified. It was deduced that while keeping all the parameters constant, the effect of cross joint orientations is prominent in the case of shallow weathered layer and reduces as the thickness of the weathered layer increases. The effect of main joint orientations is prominent in the case of a deep weathered layer and reduces as the thickness of the weathered layer decreases. Analysis of variance (ANOVA) of the obtained result indicates that all the independent variables (slope height, slope angle, weathered layer thickness, main joint set, and cross joint set) are significantly predicting the dependent variable (FOS of rock slope) and the reducing order of significance is weathered layer thickness, slope angle, main joint orientation, slope height, and cross joint orientation.

Analysis of universal joint using virtual simulation method

The guiding framework and directing section are the standouts amongst the most significant gadgets of a car. It is an extremely critical part to accomplish the steadiness and relentless development of the vehicle. Just like an insect in this part, a cross joint is formed made up of poles having some type of burdens on each pole. The poles due to the force which are applied to them tend to experience shear as well as torsion force. Movement transmission arrangement of vehicles comprises a few parts which some of the time experience disastrous disappointments. Forces combine to form a turning part and this tends to experience weakness due to variable torque. In this research paper, we have limited our investigation of just segment to understand its pressure and dislodging effect with regards to the last item. For virtual construction of the object framework, a solid works tool was utilized and for analysis purposes, ANSYS programming was utilized. Hereby using FEA methodologies we can understand as well as distinguish between different types of stresses. This can be further studied by assessing the impact on the heap, limit conditions, the geometry of the mass, and the nature of the yoke. The directing framework and guiding section are the standouts amongst the most significant gadgets of a vehicle. it is an exceptionally essential part to accomplish security and unfaltering development of the vehicle. Just like insects, it has poles which were due to cross formed at the middle of the road part having burdens on both of its pole which were joined at the middle like a cross joint which was used in cross joints. Due to forces applied on the cross joint poles, it experiences both shear as well as torsion force. Movement transmission arrangement of vehicles comprises a few segments which at times experience heartbreaking disappointments. We have optimized and analyzed the universal joint according to lattice and free size and shape methodology.

Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

The steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate S{ - }N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

A novel bionic-based substructure division method for topology optimization

In the cantilever plate structure, traditional topology optimization cannot achieve satisfactory results since topological material always focuses on one part while the other parts occupy no or few materials. To overcome this drawback, a bionic-based substructure division method for topology optimization was proposed in this paper. In this method, The designable region of topology optimization was divided into several substructures. The material layout of each subordinate topology design unit was formed for maximizing the total stiffness under a prescribed material usage constraint. The concept and optimization model of the bionic-based substructure division method was constructed. Then, the effectiveness of the method was verified through the example of a cantilever plate by comparison with the traditional topology optimization. Finally, an application example of a cross joint using the bionic-based substructure division method was provided and made by 3D printing technology. The research results show that the bionic-based substructure division method can enhance the guidance of topology optimization in finding reasonable material layout. By this method, the innovative configuration of a lighter cross joint is obtained. The application of this method improves the efficiency and effect of structural optimization.

Application of Geomembrane on the Dam of Concrete Face in a Certain Hydropower Station Project

A certain hydropower station is a concrete face rockfill dam, with the dam height of 219 m. Because of various reasons, Composite geomembrane was added on the concrete face below the elevation of 382 m. A combined impermeable system composed of composite geomememes and concrete panels is formed. This paper introduces the impermeable scheme of composite geomemmembrane, the impermeable silo design, the design of cross joint, the laying and fixing of geomemmembrane and the sealing and welding of geomemmembrane as well as its quality control and quality test and so on. The above achievements have accumulated experience for the application of composite geomememes in the anti-seepage technology of high dam.

Cyclic loading tests of earthquake-resilient prefabricated cross joint with single flange cover plate

Earthquake-resilient functions have become a frontier hot direction in the field of seismic engineering. Based on the concept of damage control, a new type of earthquake-resilient prefabricated cross joint (ERPCJ) with single flange cover plate (FCP) has been proposed. The ERPCJ is composed of a circular tubular steel column with a cantilever beam, a common beam, and a connection device. The plastic hinge will be transferred to the connection device, when the cantilever beam has been strengthened and the FCPs have been reduced. This design only requires replacement of the connection device to achieve recovery after an earthquake. In this study, seven low frequency cyclic loading tests were carried out on six specimens. The failure mode, hysteresis curve, skeleton curve, and other seismic performance indices of the joint were obtained. The influences of the weakened form, thickness and material property of the FCPs, and the gap between the beams on the seismic performance of the joint were mainly investigated. The experiments showed that the ERPCJ with reasonable parameter settings possessed good bearing capacity and hysteresis characteristics. The repair program of replacing the connection device was feasible and the requirements of earthquake resilience could be met. The ERPCJ utilizes the plastic deformation of the FCPs to dissipate the seismic energy and improve its ductility and rotation ability. In addition, thickness and material property of the FCPs, and a gap between the beams significantly affect the seismic performance of the joint. Therefore, the values of these parameters should be designed reasonably.

Theoretical and numerical study on the block-flexure toppling failure of rock slopes

Block-flexure toppling failure is frequently encountered in rock slopes. In this paper, we first proposed two theoretical models to calculate the factor of safety against block-flexure toppling, namely, step by step analysis model (LEM-SSAM) and overall analysis model (LEM-OAM). Then, we developed two special MATLAB codes for a quick stability estimation based on the proposed methods, respectively. Next, the universal distinct element code (UDEC) was used to study the failure mechanisms of block-flexure toppling. In order to realistically simulate the excavation of slope and obtain the detailed damage information of joints, we developed two FISH functions in UDEC. Finally, we conducted a comparative analysis of the limit equilibrium method and the numerical simulations through twelve theoretical models. The results show that many aspects of block-flexure toppling failure have been captured using UDEC combined with the developed FISH functions. The LEM-OAM and UDEC agree well while a larger factor of safety is obtained using the LEM-SSAM. It is found that the dip angles and friction angles of the joints dipping steeply into face have a great influence on block-flexure toppling failure while the influence of the cross joint spacing is less significant.

Process Analysis of Toppling Failure on Anti-dip Rock Slopes Under Seismic Load in Southwest China

Due to complex geological structures and strong crustal activity, geological disasters occur frequently in the upper reaches of the Yalong River, Southwest China. Toppling failure on anti-dip rock slopes is a common phenomenon; in particular, after the Wenchuan earthquake in 2008, numerous landslides caused by toppling deformation occurred in reservoir areas, seriously threatening the construction and operation of large-scale water conservancy projects and hydropower projects. Taking three typical toppling slopes in the basin as research objects, the dynamic behaviour, failure evolution, and failure plane location of toppling failure under seismic waves were investigated by shaking table tests and UDEC simulations. The test results indicated that slope angle and stratum dip angle were both inversely proportional to the stability of the slope in the tested ranges. The failure evolution of toppling on anti-dip rock slopes could be divided into four stages: (1) the development stage of tensile cracks in the strata; (2) the formative stage of tensile cracks at the crest of the slope; (3) the formative stage of toppling zones; and (4) the failure stage. Two equations were proposed to reveal the relationships between the surface peak ground acceleration and the horizontal depth of the failure plane and displacement of the slope surface. The propagation and coalescence of discontinuous cross joint in the slope and the entire failure evolution simulated by the UDEC damage model agreed well with the shaking table test results.