Greater Load Capacity Research Articles

Study on Static Biomechanical Model of Whole Body Based on Virtual Human.

Material handling tasks often lead to skeletal injury of workers. The whole-body static biomechanical modeling method based on virtual humans is the theoretical basis for analyzing the human factor index in the lifting process. This paper focuses on the study of humans' body static biomechanical model for virtual human ergonomics analysis: First, the whole-body static biomechanical model is constructed, which calculates the biomechanical data such as force and moment, average strength, and maximum hand load at human joints. Secondly, the prototype model test system is developed, and the real experiment environment is set up with the inertial motion capture system. Finally, the model reliability verification experiment and application simulation experiment are designed. The comparison results with the industrial ergonomic software show that the model is consistent with the output of the industrial ergonomic software, which proves the reliability of the model. The simulation results show that under the same load, the maximum joint load and the maximum hand load are strongly related to the working posture, and the working posture should be adjusted to adapt to the load. Upright or bent legs have less influence on the maximum load capacity of the hand. Lower hand load capacity is due to forearm extension, and the upper arm extension greatly reduces the load capacity of the hand. Compared with a one-handed load, the two-handed load has a greater load capacity.

Sustainable WPC Production: A Novel Method Using Recycled High-Density Polyethylene and Wood Veneer

This research work is focused on the development of an alternative method for manufacturing Wood Plastic Composite (WPC) panels based on Wood Veneers (WVs) and High-Density Polyethylene (HDPE) through compression molding, which enhances the physical properties, particularly, water absorption and moisture content. The aim of the present research was to develop alternative panels to replace commercial ones, which are heavily affected by hot, humid climates. In this context, the study began with the design process, which consisted of the collection and processing of primary material, production of the additional components necessary for the manufacturing process, determination of the WV ratio, and preparation of the samples. Thereafter, physical and mechanical tests were carried out on WPC, HDPE (control), commercial gypsum boards (GBs), plywood (PW), and medium density fiberboard (MDF) samples. The results indicate that the method applied to manufacture the WPC samples improved physical properties, achieving a water uptake of less than 4% in both proportions of replacement tested, in contrast to commercial panels, which reached values between 10% and 40%. In addition, a greater load capacity was achieved for lower thick elements.

Analysis of the Influence of Calculation Parameters on the Design of the Gearbox of a High-Power Wind Turbine

As wind turbine power requirements have evolved from the order of kilowatts (kWs) to the order of several megawatts (MWs), wind turbine components have been subjected to more demanding and critical operating conditions. The wind turbine must cope with higher wind loads due to larger blade sizes, which are also time-varying, and, ultimately, higher power levels. One of the challenges in the manufacture of high-power wind turbines lies in the gearbox and consists of achieving ever-greater power density without compromising efficiency, i.e., greater load capacity with lower weight (and production cost) and reduced power losses. Epicyclic geartrains are used to build the gearbox due to various advantages in relation to conventional gear systems, such as higher feasible gear ratios, higher efficiency, compactnesss, and lower weight. In this paper, several epicyclic geartrains with different structures will be analysed to reveal the influence that certain design parameters have on the size and weight of the gearbox components in the selected model and, therefore, of the gearbox itself. For this purpose, the theoretical model of the gearbox will be planned and the influence of the calculation parameters on the gearbox design will be analyzed following ISO 6336. Special emphasis is placed on the influence of the material used; the modulus and tooth width on the size and weight of the gearbox will be observed. Critical stresses are also calculated. The goal is to prepare the theoretical basis for an optimization process subject to geometric, kinematic, and dynamic constraints that will result in a gearbox as compact, energy-dense, and light as possible without compromising the service life of the components.

FEATURES OF EXISTING CONSTRUCTION TYPES OF CONNECTIONS FOR TORQUE TRANSMISSION

The main goal of modern mechanical engineering is the production of high-quality products with minimal capital investments and as little time as possible, which at the same time is accompanied by a constant increase in the complexity of the geometric shapes of parts and their accuracy, high requirements for mating surfaces and their properties, the performance of assembly products and their operating conditions. Elements of splined and splined joints make up a significant share of machine-building products among a wide variety of other products. There is a significant group of plug connections used for torque transmission, in which the plug is made using special design conditions of assembly. this group primarily includes keyed and slotted connections. These are standard methods of joining, in which all structural parameters, materials, manufacturing accuracy and operating conditions, as well as assembly are fully determined by state standards.
 The considered keyed and splined connections are intended for the transmission of torque from the shaft to the part mounted on it (pulley, gear wheel, etc.) and vice versa. The advantages of key joints are their simplicity and reliability in operation, but they weaken the shafts and the hub with key grooves and cause stress concentration. Compared to splined joints, spline joints have a greater load capacity, better center the part on the shaft and give a lower stress concentration, which increases the fatigue strength of the shafts, but they are more difficult to manufacture.

A descriptive study of weaned piglet transport practices in Alberta, Ontario, and Saskatchewan, Canada between 2014 and 2018.

Canadian transport practices for shipments of newly weaned piglets are not well-described despite documentation requirements for those conducting the movement of these animals. The objective of this study was to describe the characteristics of weaned piglet transport events that occurred between 2014 and 2018 using records provided by five Canadian swine companies. Following cleaning and validation, the dataset included records from 6203 transport events involving the transport of approximately 6.9 million piglets (5.7kg, 4.1-7.9kg) from 62 origin sites in Alberta, Ontario, or Saskatchewan, Canada. This represents approximately 4.7% of the piglets estimated to have been weaned in Canada between 2014 and 2018, and 1.7% of sow farms in Canada according to 2016 National census data. Most transport events ended at farms in Canada (71.3%), while the remaining delivered piglets to one of eight American states. The predominant trailer types used were Straightdeck (51.4%) and Potbelly (36.6%), but this did not reflect the number of piglets transported as Potbelly trailers have greater load capacity. Transport events most frequently involved loading piglets from one origin barn and delivering them to a single destination barn (78.1%). Only transport events involving export to the United States picked up piglets from, or delivered them to, more than one farm site. Most transport events had very short trip distances (median distance: 48.0km; IQR: 497.0), but a marked range was observed (1.8-2931.2km). Average daily temperature data matched to the transport records by origin and destination location demonstrated ambient environmental conditions during these transport events ranged from -30.3-28.7°C. Overall, less than 10% of transport events had mortality occur. Comparable with other observational studies documenting weaned piglet mortality, the average in-transit mortality rate observed over the multiple seasons, companies, trip distances, and other characteristics in this dataset was 0.027%. However, instances of mortality over 1% did sporadically occur and could translate to considerable losses given the large load sizes common for piglets of this age and size (median load size: 1105 piglets; IQR: 1036 piglets). These data provide a better understanding of the interconnectedness of the Canadian swine industry as well as common transport practices which may inform future research on disease transmission in swine transport networks, or piglet welfare during transport. Additionally, variables that were not present in this dataset that would further strengthen these types of investigations are highlighted (e.g., space allowance).

Demountable reinforced concrete slabs using dry connections

The results of an experimental investigation of a new dry connection for reinforced concrete slab elements are presented. Seven full-scale slabs were tested; one slab was monolithic and used as a control specimen, while the other six were assembled using top and bottom steel plates joined by steel bolts with high tensile strength. Two connection scenarios were investigated – a simple bolted connection and a connection with a shear key. The parameters studied were the use of stirrups at the connection section, the step size of the shear key, the bolt diameter and the number of bolts. The test results showed that using a shear key at the assembled section in demountable slabs was more efficient than the simple bolted connection, providing higher flexural stiffness, greater load capacity and less deflection. However, increasing the shear key step size improved the flexural performance of the demountable slabs. In addition, adding stirrups in the assembled section enhanced the flexural stiffness and the total load capacity of the demountable slabs. Predictions of the moment capacity and deflection of the demountable slabs showed reasonably good agreement with the experimental results but, to be generalised, additional calibrated data from experiments are required.

Multi-objective route optimization of urban cold chain distribution using electric and diesel powered vehicles

Increasingly serious urban road congestion and environmental pollution have led some cities to impose restrictions such as limiting certain types of vehicles and the areas in which they can operate and introducing subsidies and other incentives for electric refrigerated vehicles. As a result, both internal combustion engine (ICE) refrigerated vehicles and electric refrigerated vehicles will be used together in urban cold chain distribution for a long time into the future. Most current studies are concerned with mixed vehicle type allocation or mixed vehicle routing problems. Although there are some studies that combine the two, there has been little research into the effects of low carbon emission and multiple objective optimization on distribution and routing for a mixture of vehicle types. This paper describes the creation of an optimized decision-making cold chain distribution model that includes different types of distribution vehicles and different route optimization criteria that represent the three enterprise objectives of minimal cost, minimum carbon emissions and minimum distance. The decision criteria are influenced by conflicting benefits offered by ICE and electric refrigerated vehicles as well as government subsidies for electric refrigerated vehicles and carbon emission trading by logistics enterprises. A chaotic particle swarm optimization algorithm was used to analyze a cold chain distribution system in Wuhan, Hubei Province, China. The results show that: (1) The choice of enterprise distribution models and the vehicles and routes determined are closely related to enterprise goals. To minimize total cost, ICE refrigerated trucks with less load capacity and electric refrigerated trucks with greater load capacity are preferred. To minimize carbon emissions, ICE refrigerated trucks and electric refrigerated trucks with less load capacity are preferred. To minimize total distance, ICE refrigerated trucks and electric refrigerated trucks with greater load capacity are preferred. (2) As the value of government subsidies increases, the total load capacity of electric refrigerated vehicles also increases, the distribution routes change, and total carbon emissions and total distribution costs decrease. (3) When carbon emission trading prices increase, the number of electric refrigerated vehicles gradually increases, the distribution path changes, the total distribution costs increase, and total carbon emissions decrease. Some suggestions are made for government to determine subsidies for electric refrigerated vehicles and carbon emission trading policies that will guide the choice of distribution vehicles and affect the criteria used for route optimization by cold chain logistics enterprises.

The Effects Of Differing Density Of Swim-Training Sessions On Shoulder Range Of Motion and Isometric Force Production In National and University Level Swimmers.

Well-developed physical qualities (i.e., greater load capacity) in athletes can provide protection against injuries. Although higher competitive level swimmers have more developed physical qualities, no studies have investigated how physical qualities of the shoulder respond to a swim-training session in different competitive levels. To compare baseline shoulder external rotation range of motion (ER ROM) and isometric peak torque of the shoulder internal rotators (IR) and external rotators (ER) between national and university level swimmers with differing training volumes. To compare the post-swim changes of these physical qualities between groups. Cross-sectional. Ten male swimmers (age= 18.7 ± 1.2 years) were divided into high-load (N= 5 national-level, weekly swim-volume= 37.0 ± 2.7 km) and low-load groups (N= 5 university-level, weekly swim-volume= 6.8 ± 1.8 km). For each group, shoulder active ER ROM and isometric peak torque of the shoulder IR and ER were measured before and immediately after a high-intensity swim-training session (for each group, the hardest swim-session of the week was analyzed). The results were evaluated by the level of significance (p-value), effect size, and whether changes exceeded the measurement error. University-level swimmers had lower baseline ER torque (p= 0.006; d= 2.55) and IR torque (p= 0.011; d= 2.42) than national-level swimmers. For post-swim analysis, ER ROM decreased more in university swimmers (change= -6.3° to -8.4°; d= 0.75-1.05) than national counterparts (change= -1.9° to -5.7°; d= 0.43-0.95). Greater drops in rotation torque were found in university swimmers (IR change= -15% to -21.0%; d= 0.83-1.66; ER change= -9.0% to -17.0%; d= 1.14-1.28) compared to national swimmers (IR change= -10.0% to -13.0%; d= 0.61-0.91; ER change= -3.7% to -9.1%; d= 0.50-0.96). The average change of all tests in university swimmers exceeded the minimal detectable change (MDC), whereas in national level swimmers some tests exceeded the MDC. Despite this, only post-swim ER torque in the dominant side (p= 0.003; d= 1.18) was significantly lower in university swimmers (possibly due to the small sample size). University swimmers have less baseline shoulder external and internal rotator torque and had greater drops of all shoulder physical qualities after a swim-training session, which may have implications for injury risk. However, due to the sample size, the results have to be interpreted with caution. 3.

Probability and number of bruises in bovine carcasses according to animal type, handling and transport.

The aim of this study was to evaluate pre-slaughter risk factors on the probability of bruising and the number of bruises in different regions of the bovine carcass. The study evaluated the data from 4061 batches of slaughtered cattle, totalling 199,026 carcasses, from Hereford and Aberdeen Angus animals in crosses with continental European breeds and Zebu cattle. The factors that caused injury were sex, handling conditions (score), vehicle type, vehicle load density (kg/m2), travel time (minutes), travel distance (kilometres), physiological maturity (dentition), animal reactivity (score), and carcass fat (score). The type of vehicle had the greatest influence on the probability of carcass bruising and affected all carcass cuts. More bruising occurred in vehicles with a greater load capacity. A higher chance of bruising was seen in groups of older animals, those with an excitable temperament and, especially, in groups of females. Higher load densities during transport resulted in a greater chance of bruising occurring in all cuts except the hindquarters. Distance and travel time are unstable in the models, but also detrimental, increasing the probability of bruising and the number of bruises in the various cuts. The results of this study suggest that good practices in the welfare, handling and transport of the animals, as well as training the personnel responsible for their handling, should be adopted to minimise the risk of injury at different locations on the carcass.

ALTERAÇÕES FISIOLÓGICAS DOS ATLETAS DE ARTES MARCIAIS EM TREINOS DE ALTITUDE

ABSTRACT Introduction: Recent studies have shown that altitude training can significantly improve hemoglobin content in athletes. This allows for greater oxygen transport to the muscles and, consequently, greater load capacity during training. However, there is no confirmed evidence of athlete-specific training in martial arts. Objective: Explore the load capacity and ability changes caused by high altitude training in athletes. Methods: The research selected ten high-level martial arts athletes as volunteers to compare the functional changes caused by high-altitude training. Physical and functional data were collected before the beginning of the experiment and at its conclusion after three weeks. Results: Measured abilities were significantly improved after 11 days of altitude physical training. After 21 days of altitude training, these abilities improved significantly. The urea nitrogen and creatine kinase values increased rapidly with increasing load intensity in the first stage, peaked in the second stage, and decreased in the third stage. Conclusion: Training in the low-pressure hypoxic environment at high altitude, using dual stimulation of hypoxia and exercise to make the athletes stress response, can stimulate the physical potential to achieve a range of physiological abilities to improve the body’s resistance to hypoxia. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

A fast transient response current-feedback low-dropout regulator with dynamic current-enhancement technique

This paper proposed a dynamic current-enhancement technique based on AC coupling network and feedforward compensation capacitor for current-feedback low-dropout regulators (LDOs). Compared with traditional reported current-feedback LDOs, this design exhibits wider input voltage range, greater load capacity and fast transient response, yet no extra power consumption is introduced. Moreover, a complete stability analysis under full load range is given in this paper. The proposed LDO is fabricated in SMIC 0.18μm CMOS process. The input voltage range is 0.8–2.2 V and the maximum load current is 50 mA. The experiment results indicate that the overshoot and undershoot are 76 mV and 141 mV respectively when the load current is varied from 0 to 50 mA within 300 ns under the load of 100 pF load capacitor.

Annealing effect on mechanical properties and strain localization of a Zr-based metallic glass under shear

Fracture behavior under shear load is important for understanding the intrinsic deformation and fracture mechanism of metallic glasses (MGs). However, due to the limit forming of MGs, shear testing still remains a challenge in terms of traditional mechanical methods. In this study, the annealing effect on mechanical properties and strain localization of Zr52.5Cu17.9Ni14.6Al10Ti5 MG were investigated under shear load using a digital image correlation (DIC) method. Firstly, the shear strength, as well as fracture angle and fracture surface morphology, were systematically analyzed and compared for MGs annealed at different temperatures. Secondly, the shear strain evolution in calculated region by DIC method was obtained from full-field deformation measurements. Data analysis revealed that a higher degree heterogeneity of local strain corresponded to a lower annealing temperature, which correlated with a greater load capacity. Thirdly, a novel method was proposed for gauging shear modulus by bimodal Gaussian distribution. These findings have implication for understanding the deformation behaviors and fracture mechanisms of MGs under shear.

Структурный синтез и анализ механизмов с выходным звеном, совершающим одно поступательное и два вращательных движения

The article considers mechanisms based on a hinged flat parallelogram with an additional link, ensuring the ability to maintain the insertion point of the tool installed on the output link. A rotational kinematic pair coupled to the base allows the plane of rotation of the articulated parallelogram to change the angle of inclination. The proposed design should have a greater load capacity than the available analogues, since the rotational kinematic pair mating the articulated parallelogram with the base is made in the form of two semi-axes, and the output link is located between the intermediate links of this parallelogram. The equality of the rotation angles of the output link and the intermediate links of the articulated parallelogram is ensured by the presence of additional links or belt drives. Three-dimensional models of these mechanisms are presented, and their structural synthesis is carried out in various modifications. Depending on the modification, it becomes possible to apply such mechanisms not only in industry, including additive technologies, but also in the field of medicine during surgical operations and in the study of plasma properties.

Strengthening of Non-Engineered Building with Steel Plate to Increase Seismic Performance

Residential buildings are included in the category of non-engineered buildings that suffered the most damage during an earthquake. This is because most of the building materials used and the working techniques, especially the reinforcement, do not meet the requirements. This research will be reviewed numerically using ATENA software on three types of numerical models, each of which represents non-engineered buildings, engineered buildings and reinforcement models with steel plates. The results showed that the non-engineered building model would experience the largest deflection and the smallest load bearing capacity, while the other 2 models experienced a smaller displacement with a greater load capacity. The best performance is shown in models with steel plate reinforcement, so that the reinforcement of steel plates in non-technical buildings will effectively increase the performance of non-engineered buildings.

Effects of bolted connections on behaviour of timber frames under combined vertical and lateral loads

In this paper, a new bolted beam-column connection comprising of top-and-seat steel angles and bolts was used in timber frames and its influence on structural behaviour was determined through comparisons with connections with slotted-in steel-plates. In the experimental programme, three full-scale timber frames were tested to failure under combined vertical and lateral loads and their load capacity and lateral stiffness were obtained. Different failure modes of frames were also observed at beam-column connections and column bases. Strains at selected sections of beams and columns were measured by using strain gauges and rotations of beam-column connections and column bases were also captured by using displacement transducers. Bending moments at beam and column ends were calculated based on plane-section assumption and moment-rotation relationships of beam-column connections and column bases were established. Test results showed that timber frame with top-and-seat-steel-angle connections could develop 44% higher lateral stiffness and 20% greater load capacity than the frame with slotted-in steel-plate connections. The increases in stiffness and load capacity mainly resulted from the 3.0 times higher rotational stiffness of top-and-seat-steel-angle connections than that of slotted-in steel-plate connections. By decreasing the cross-section of beams and columns in the frame with top-and-seat-steel-angle connections, the rotational stiffness of connections was slightly reduced, but the connection could still sustain significant bending moments under lateral loads.

Building a Model to Reconstruct the Hellenistic and Roman Road Networks of the Eastern Desert of Egypt, a Semi-Empirical Approach Based on Modern Travelers’ Itineraries

The Egyptian Eastern Desert, the part of the Sahara Desert that connects the Nile and the Red Sea, is rich in natural resources and meshed with multiple networks. The adoption of the camel as the main mode of transportation in the 1st millennium BC, faster and with a greater load capacity than humans or donkeys, dramatically changed the logistics used to cross this difficult terrain. Our objective, therefore, is to understand and reconstruct circulation in the region during Antiquity through location factors and the evolution of roads. For this purpose, a least-cost network specific to camel movements has been created for this arid and mountainous region. The network is based on the reconstructed itineraries of modern travelers (18th and 19th centuries) who crossed the region under similar conditions to ancient ones. These routes and the travelers’ diaries have enabled us to analyze the main travel constraints; they provide a set of data to calibrate the different movement factors of camel caravans and to validate the calculated least cost paths. The modeled network takes into account transport infrastructures, navigation conditions in plain areas, difficulties of the terrain surface, and the topographical constraints specific to camels. This methodological paper details our approach from the description of movement factors, their mapping, and their use in least cost algorithms to the creation of a network covering 253 archaeological sites and 204 desert watering places. It aims to provide the archaeological and GIS communities with the method and tools to reproduce itineraries based on the hypotheses of movement and empirical data. For this purpose, the data is available and documented by a data paper.

Modeling and Load Capacity Analysis of Reciprocating Hybrid Linear Guideway With Annular Groove and Sloped Recesses

Abstract In this work, we research a reciprocating hybrid linear guideway and study its load capacity. This hybrid guideway's bearing surface is designed with an annular groove and two sloped shallow recesses. The analysis is based on modeling by mass-conserving cavitation algorithm (p − θ cavitation algorithm), where a modified smoothing switch function is raised for better convergence. Focusing on the normal direction to reciprocation, the load-guideway system is simplified as a single-degree-of-freedom linear time-varying system and solved by Newmark-β method. Due to the hybrid guideway's time-varying dynamic characteristics, there is a normal vibration in reciprocation. By analyzing two typical load cases in detail, the results indicate that the hybrid guideway has greater load capacity than the hydrostatic guideway, and the normal vibration is small enough for most engineering situations.

Dynamic performance of vehicle in high-speed freight EMU equipped with four double-axle bogies

Size and weight limitations mean that ordinary railway vehicles with two double-axle bogies cannot deliver some extremely heavy cargo and products. Thus, a newly designed high-speed freight electric multiple unit (EMU) equipped with two bogie groups each with two double-axle bogies connected by a transition frame is an alternative means of transporting heavy products because of its greater load capacity. However, because it is still in the design stage, its dynamic performance is yet to be researched, something that is urgently required because of the more-complicated structure and more-intensive wheel-rail interactions than those of traditional high-speed railway vehicles Therefore, to reveal the dynamic performance, this study establishes a three-dimensional dynamic model of a trailer vehicle in a high-speed freight EMU equipped with four double-axle bogies based on the classical theory of vehicle-track coupled dynamics. In this dynamic model, the vertical, horizontal, rolling, pitching, and yaw motions of the major components excited by random irregularities in the track geometry are considered fully. The results indicate that the derailment coefficient and stability index of this vehicle are both at excellent levels for the simulated conditions. The wheel unloading ratio appears to be larger but still within the safety range when the vehicle runs in a straight line, but it is close to or can even exceed the limit value when the vehicle runs at 400 km/h on a specified curved line.

Blast responses of concrete beams reinforced with steel-GFRP composite bars

Steel-GFRP (glass fiber reinforced polymer) composite bars (SGCBs) have advantages in corrosion-resistance and high load-bearing capacity endowed by GFRP, as well as ductility inherited from steel bars. They can be used as reinforcements in concrete protective structures. Two types of composite-bar reinforced concrete beams (CRCBs) were designed and casted. Explosion experiments reveal that cracking and spalling are the main damage patterns of the CRCBs. Composite bars reduce the plastic deformation and the residual deflection compared with the steel-bar reinforced concrete beams (SRCBs). Anti-blast ability is evaluated by quasi-static four-point-bending experiment on exploded beams. Intact CRCBs have three typical deformation stages, including elastic, elastoplastic and post-plastic deformations, and fail when the mid-span flexural crack almost runs through the beam. GFRP bars make the CRCB have much greater load capacity than the SRCB. Exploded beams have similar deformation and failure styles with the unexploded beam and even have greater load capacity than the unexploded SRCB. Having both high load capacity and excellent ductility, the SGCBs have advantages over steel bars in protective structures in some cases.

Causes of bruising in carcasses of beef cattle during farm, transport, and slaughterhouse handling in Brazil.

This study aimed to assess preslaughter factors responsible for the occurrence of bruises to front, rib, loin, hip, and round sites of cattle carcasses. Data from the slaughter of 148 loads of cattle were assessed, totaling 4,611 carcasses. Evaluated bruising factor variables were animal gender, journey distance (km), vehicle type (m²), journey time (hours), load density (kg/m2 ), handling and facilities conditions (optimal, acceptable, and unacceptable), and unloading waiting time (min). Gender had the strongest influence on carcass bruising, being the first variable to enter in the majority of models related to the carcass sites. Female carcasses displayed higher bruising in all sites. Densities above 401kg/m² caused more bruising. With the exception of the loin, unacceptable, and acceptable conditions assigned to farm facilities and handling resulted in higher average bruising. Articulated vehicles with a greater load capacity were more likely to cause bruising. The effects of variables causing bruises act differently in the various carcass sites. In this sense, the results of this study suggested possible management practices for specific problems during the preslaughter period to minimize losses by bruising to different carcass sites.