Type Of Clutch Research Articles

Designing and Analysis of Multiplate Clutch by ANSYS Software

In this paper, the multi-plate clutch design process will be presented. As we know, the clutch is very useful in engaging and disengaging the vehicle's transmission with the engine. There are many types of clutches on the market. This study presents an in-depth analysis of the design of multi-plate wet clutches for automotive applications. It explores different design techniques, challenges and advances, focusing on aspects such as contact characteristics, thermal management, structural integrity and material selection. Additionally, the integration of multi-plate clutch systems with hybrid powertrains and the implications of the electrification trend are also explored. By addressing key aspects of multi-plate clutch design and identifying future research directions, this article aims to contribute to the advancement of automotive engineering, promoting innovations new to improve the performance, efficiency and durability of modern vehicles. The design proposed in this paper is rated to be 93% accurate. In our proposed system, the proposed design has a deformation of 0.0000187 mm and can withstand a maximum nominal stress of 0.20076 N/mm2,

High‐Performance and High Bandwidth Electroadhesive Clutch Enabled by Fracture Mechanics and a Dielectric Nanoparticle‐Based High‐k Composite

AbstractClutches are integral components in robotic systems, enabling programming of system stiffness and precise control over a wide range of motion types. While different types of clutches exist, electroadhesive (EA) clutches present several key advantages, such as flexibility, low mass, low power consumption, simplicity, and fast response. Achieving high EA stress in EA clutches has remained a challenge, however, necessitating high voltage input or a large contact area to achieve the desired force. In this work, an EA clutch is proposed with a high EA stress achieved by taking fracture mechanics into account and using a high dielectric composite layer while still maintaining a comparable high switching speed to other dielectric‐based EA clutches. The maximum EA stress is observed to be 108.8 N cm−2, which is four times larger than what has been reported previously among dielectric‐based EA clutches at room temperature. This high EA stress clutch can facilitate miniaturization and lower the operating voltage as well as extend to high load capacity applications. The proposed approach holds promise for advancements in various domains, including haptics (both kinesthetic and cutaneous), exoskeletons, walking robots, and other systems that require compliance, low mass, and precise force control.

A New Type of Hydraulic Clutch with Magnetorheological Fluid: Theory and Experiment.

This paper presents a new type of hydraulic clutch operating by means of magnetorheological (MR) fluids and the results achieved from both theoretical analysis and experimental measurement. A hydraulic clutch system with MR working fluid and a rotating magnetic field located was designed. The clutch was based on the principle of using a rotating magnetic field created by an alternating current electromagnet to set the MR fluid in motion. To test the hydraulic clutch with a rotating magnetic field, MR fluids were produced by our laboratory, consisting of solid iron particles of various diameters mixed with a silicone oil. With MR working fluid and a rotating magnetic core was designed. The rheological properties of the MR fluids were assessed on the basis of tests carried out with a Brookfield DV2T rheometer equipped with a magnetic device for generating a magnetic field. The characteristics of the hydraulic clutch were tested on a specially built test stand. It was found that the torque transmitted by the clutch increased with the rotational speed of the magnetic field and with a lower rotational speed of the beaker in which the working fluid was placed. It was also found that the greatest torque occurred with the working fluid with the highest iron content. Based on the analysis of the structure and characteristics of the clutch in which the magnetic field is used, it has been shown that the design of the developed clutch is similar to that of an induction clutch, and its characteristics correspond to the characteristics of the eddy current clutch. Therefore, the proposed new clutch with MR fluid and rotating magnetic field can be applied to stationary power transmission systems in a manner similar to an eddy current clutch.

Frogs and flows: Using life‐history traits and a systematic review to establish water‐dependent functional groups for stream frogs in New South Wales, Australia

AbstractHydrological alteration has contributed to the global decline of stream frogs. Flows support stream frog reproduction, juvenile development, food resources, and maintain habitats for all life stages. At present, there is a lack of information regarding the specific water requirements necessary for the conservation of stream frogs. To address this gap, we developed a traits‐based approach that serves as a valuable tool for grouping and prioritising water‐dependent stream frog species to inform future research priorities and environmental flow design. In this study, we focussed on 53 Australian frog species and analysed eight species traits to develop water‐dependent functional groups for stream frogs. We classified frogs based on their level of water dependency using an agglomerative hierarchical clustering analysis and a systematic review of water requirements and water management threats. The distinguishing traits that determined functional groups were: tadpole body type, egg clutch type, stream breeding habitat type, and documented association with flowing water and water permanence. Our study identified two distinct water‐dependent groups: facultative stream spawners, capable of reproducing in both stream and non‐stream habitats, and obligate stream spawners, restricted solely to stream habitats. Importantly, we highlight that the obligate stream spawners are the most sensitive group to within‐channel flow alteration and should be prioritised for water management decisions in lotic environments. This study represents the first comprehensive overview of the importance of hydrology for stream frogs and identifies the critical need for additional research and validation to enhance our understanding of stream frog responses to flows regimes.

Nestlings reared by males are in better body condition than those reared by females in uniparental European Penduline Tits

Conditions encountered during early development affect future survival and reproduction in many bird species. For parents, it is important what body condition the nestlings will achieve at fledging because the condition affects the offspring’s chances to survive and reproduce in the future. However, there is a trade-off between the number of nestlings and their condition. We studied parental behaviour and nestling body condition in uniparental Penduline Tits. In this small passerine, the parental care (incubation and food provisioning) is provided by the female only (49% of clutches in the study population) or the male only (15%). In addition, over a third of clutches are deserted by both parents before the start of incubation. We found that female-only cared clutches had more eggs and nestlings and produced more fledglings than male-only cared clutches. The incubation behaviour and incubation temperature in both types of clutches were similar. The provisioning rate per brood was positively, and the provisioning rate per nestling was negatively, correlated with brood size. Although males cared for smaller clutches, parent sex was not significant in both models of provisioning rates (per brood and per nestling). Moreover, the provisioning rate did not predict the brood’s average nestling condition. However, nestlings reared in broods with male care were in better condition than those reared by females. At the age of 13 days, they had a higher scaled mass index (describes the relative size of energy reserves) and higher haemoglobin levels. The results suggest that the lower productivity of male-only cared clutches, compared to those cared for only by females, may be compensated by the higher condition of nestlings. Information about the recruitment success of broods cared for by males and females will be necessary to test this prediction.

Certain concepts and definitions of the physical process of wear of friction discs of sewing machine clutches

The article covers analytical research of the performance of the pads of the friction clutch of the sewing machine. The results of research showed that the wear resistance of the pads decreases with increasing temperature. The wear resistance of pads made of different materials tested on the same type of friction clutch of sewing machine is different. The research has been carried out to determine the maximum value of the specific work of slipping and thermal impulse which determines the characteristics of the temperature field of the friction pair which significantly affects the wear resistance of the friction interface. The wear resistance of friction clutches which are one of the main characteristics that determine the reliability and durability of the friction assembly has been studied.

Study of dynamic wedging performance of the multi-shape sprag clutch

The dynamic contact parameters such as contact force, contact stress and rotational speed fluctuate with time during the actual operation of a sprag clutch. To this end, ANSYS LS-DYNA is applied to simulate the dynamics of various types of sprag clutches with different wedge surfaces to obtain the curves of speed, contact force, and windup angle of each component during operation with time. The dynamic wedging performance of the all-phase type and the PCE (positive continuous engagement) type clutch is compared and analyzed, and the effect of the change of contact angle on the dynamic wedging performance of the sprag clutch with logarithmic and Archimedean spirals is investigated, and the dynamic wedging performance of the three types of sprag clutches is compared and analyzed to guide the design of multi-faceted sprag clutches.

Rocky nests are better nesting sites than woodpecker cavities for the Eastern Rock Nuthatch Sitta Tephronota

The reproductive success of birds depends on many factors, including nest construction and placement. In the mountainous regions of southwestern Iran, broods of Eastern Rock Nuthatch Sitta tephronota were surveyed in 2016 and 2017. During the study, 11 broods in rocky cavities and 16 in abandoned Syrian woodpeckers’ Dendrocopos syriacus tree cavities were compared in terms of breeding performance (phenology, clutch size, hatching success, number of fledglings, breeding success). The Eastern Rock Nuthatch began egg-laying on March 24 and continued until April 15. The number of eggs in the clutch ranged from 3 and 7 (mean 5.6±1.19, median 6, N = 27). The two types of clutches compared usually contained 6 eggs, and the number of nestlings was statistically lower in tree cavities than in rocky nests. Hatching success was almost 30% higher in rocky nests than in tree cavities. In broods located in trees, 4 nestlings hatched most often (42%, N = 12), and in rock nests, 5 nestlings hatched (50%, N = 10). Rocky nests were also statistically greater (by over 40%) for breeding success. For all analysed broods and broods with success, roughly two extra fledglings left the rocky nests compared with tree cavities. 5 fledglings (50%, N = 10) most often left rocky nests, whereas, in general, 4 fledglings (50%, N = 10) left tree nests. Research results did not confirm that woodpecker cavities are safe nest sites for cavity dwellers.

Wymagania stawiane mechanizmom napędów kół czerpakowych koparek wielonaczyniowych kołowych eksploatowanych w utworach trudno urabialnych

State of the art and reasons for undertaking modernization activities of bucket wheel drive mechanisms of BWEs operating of domestic lignite open cast mines have been discussed in the paper.The distribution of loads and mass moments of inertia acting on the BWE mining system has been given. The applied overload protections in bucket wheel drive mechanisms in the form of various types of clutches have been presented. The gears and motors of bucket wheel drives have been described. Examples of modernized bucket wheel drive mechanisms have been given. List of requirements for bucket wheel drive mechanisms which should be met by BWEs operating in hard mineable soils has been presented.

Experimental Study of Drag Torque between Wet Clutch Discs

The development of automatic gearbox control systems contributes to their increasing popularity. By raising the number of gears and sophisticated algorithms, the reduction of fuel consumption is feasible regarding traditional manual transmissions. The continuously variable transmissions (CVT) are also growing their share of the market. Wet clutches are employed in all types of automatic transmissions, but because of oil viscosity, when such a type of clutch is disengaged, the drag torque phenomenon occurs. This deteriorates the global efficiency of the transmission system. To recognize the nature of this drag torque and how it is influenced by the main parameters (distance between plates, value of oil flow rate lubricating clutch, oil temperature, rotational speed between plates), a new test stand has been designed and assembled. The value of rotational speed has been studied up to 7000 rpm which is novel in literature. Due to strongly nonlinear dependences, the achieved results can contribute to designing more efficient clutch systems due to the strongly nonlinear nature of observed phenomena.

A higher incidence of moult–breeding overlap in great tits across time is linked to an increased frequency of second clutches: a possible effect of global warming?

The rise of temperatures due to global warming is related to a lengthening of the breeding season in many bird species. This allows more pairs to attempt two clutches within the breeding season, thus finishing their breeding activity later in the season and therefore potentially overlapping these with post–breeding moult. We tested whether this occurred in two Spanish great tit Parus major populations. The proportion of pairs laying second clutches increased from 1 % to 32 % over the study period in one of the populations (Sagunto, 1995–2019), while it did not change in the other (Quintos, 2006–2019; mean 5 %). We did not find any temporal trend for moult start date of late–breeding birds in any population. The proportion of individuals of both sexes that overlapped moult and breeding increased in Sagunto. For this latter population, sex and age, but not clutch type, contributed to the variability in the probability of overlapping in late–breeding individuals, this being higher for first–year males and lower for older females.

Life-history trade-offs, density, lay date—not personality—explain multibroodedness in great tits

AbstractIn various taxa, multibroodedness is a common breeding strategy. Life-history theory predicts that individuals can increase fitness by producing multiple broods within a season. Despite the apparent increase in the number of offspring parents might produce per season, not all individuals are multibrooded, suggesting a trade-off. We studied ecological and behavioral factors influencing the initiation of second clutches in great tits (Parus major), an optionally multibrooded bird species, by distinguishing two types of clutches: replacement versus true second clutches, produced after failure versus successful first breeding attempts, respectively. We predicted which lay date, density, and investment in first clutches would decrease the probability of initiating a second clutch, but which faster exploring behavioral types with a faster pace-of-life would be more likely to be multibrooded. The probability of initiating true second clutches varied negatively within-individuals with lay date and breeding density. The initiation of replacement clutches instead varied negatively among-individuals with lay date and density, suggesting nonrandom settlement of behavioral types across environments. Individuals were less likely to be multibrooded when producing many offspring from their first clutch, suggesting within-year reproductive trade-offs, similar to previous studies. No previous research has linked personality to multibroodedness; here we show which neither the repeatable nor the plastic part of an individual’s exploratory behavior predicted multibroodedness. We confirmed our prediction which the resolution of trade-offs may occur either at the within- or among-individual level. Our research contributes to the understanding of life-history evolution in the wild by studying the mechanisms shaping multibroodedness within seasons.

Species' traits drive amphibian tolerance to anthropogenic habitat modification.

Anthropogenic habitat modification is accelerating, threatening the world's biodiversity. Understanding species' responses to anthropogenic modification is vital for halting species' declines. However, this information is lacking for globally threatened amphibians, informed primarily by small community-level studies. We integrated >126,000 verified citizen science observations of frogs, with a global continuous measure of anthropogenic habitat modification for a continental scale analysis of the effects of habitat modification on frogs. We derived a modification tolerance index-accounting for anthropogenic stressors such as human habitation, agriculture, transport and energy production-for 87 species (36% of all Australian frog species). We used this index to quantify and rank each species' tolerance of anthropogenic habitat modification, then compiled traits of all the frog species and assessed how well these equipped species to tolerate modified habitats. Most of Australia's frog species examined were adversely affected by habitat modification. Habitat specialists and species with large geographic range sizes were the least tolerant of habitat modification. Call dominant frequency, body size, clutch type and calling position (i.e. from vegetation) were also related to tolerance of habitat modification. There is an urgent need for improved consideration of anthropogenic impacts and improved conservation measures to ensure the long-term persistence of frog populations, particularly focused on specialists and species identified as intolerant of modified habitats.

Implications of nest relocation for morphology and locomotor performance of green turtle (Chelonia mydas) hatchlings

Sea turtle scute abnormalities are observed in higher proportion in hatchlings compared to adults, suggesting that hatchlings with a non-modal scute pattern (NMSP) have a lower chance of surviving to adulthood. In this study, we collected 732 newly emerged hatchlings from Redang Island, Malaysia, and compared their scute classification, size, and mass to fitness correlates (self-righting ability, crawling speed, and swimming speed). We investigated the proportion of hatchlings from each nest with NMSP to determine if there was a correlation with incubation duration or clutch relocation. We found relocated clutches at Chagar Hutang Turtle Sanctuary had a significantly shorter incubation duration with a higher proportion of NMSP compared to in situ clutches. Hatchlings’ mass were significantly heavier from in situ clutches compared to relocated clutches, although there were no significant differences of hatchling speed based on scute classification or clutch type. The difference of hatchling mass between in situ and relocated clutches could affect predation and mortality rates on recently emerged hatchlings. These findings have important conservation implications, suggesting that relocation should only be implemented on clutches with a high potential to be disrupted or with a low chance of survival if left in situ. Our findings highlight the need for a standard procedure when clutch relocation is used as a conservation strategy. Relocation should replicate natural nest dimensions by duplicating both nest width and depth, and clutches should be relocated to similar shade conditions as the natural nest.

Analysis of Factors Affecting Vibration During Wet Clutch Engagement

The shift characteristics of a wet clutch mainly depends on the variation characteristics of the friction coefficient during clutch engagement. Therefore, by analyzing the dynamic friction transmission mechanism of wet clutch engagement, a numerical simulation of the shift engagement of a certain type of vehicle clutch is performed based on a dynamic model of the power transmission system of a vehicle with four degrees of freedom. We discuss the effect of the damping coefficient of the wet clutch transmission system, the moment of inertia of the driving disc, the moment of inertia of the driven disc, the stiffness of the transmission shaft, and the variation law of the dynamic friction coefficient on vibration and its effect on shift engagement. The results show that under the condition of a fixed speed difference, with a greater gradient change in the dynamic friction coefficient over time, shift engagement vibration occurs and increases. By appropriately increasing the damping coefficient, the moment of inertia of the driving and driven discs, and the rigidity of the drive shaft, the vibration amplitude of clutch shift engagement can be effectively reduced. The research of dynamic friction coefficient can accurately analyze the vibration of the clutch engagement, which provides a reference for the optimization design of automatic transmission.

A guild classification system proposed for anuran advertisement calls

Zoologists have widely acknowledged the utility of classification systems for characterising variation in anuran egg and clutch types, tadpole morphotypes, embryonic and tadpole development, amplexus types and reproductive modes. These classification systems have facilitated unambiguous communication between researchers, often working in completely different fields (e.g. taxonomy, ecology, behaviour), as well as comparisons among studies. A syntactic system, classifying anuran call guilds, is so far lacking. Based on examination of the calls of 1253 anuran species we present a simple, easy to use dichotomous key and guild system for classifying anuran advertisement calls – the call type most frequently emitted by anurans and studied by researchers. The use of only three call elements, namely clearly-defined calls, notes, and pulses, plus presence or absence of frequency modulation, allows assigning all currently known anuran advertisement calls to one of eight distinct call guilds defined here. This novel toolkit will facilitate comparative studies across the many thousand anuran species, and may help to unravel drivers of anuran call evolution, and to identify ecological patterns at the level of acoustic communities.

Automotive vehicle clutch engagement characteristics for different types of force trajectories

Vehicle driveline of automobile, which transmit engine energy to the wheels, is complex system with nonlinear behavior. In manual transmission clutch engagement performance depends upon driver’s skill and is significantly affected by traj ectory of clutch force during engagement process. In this work different types of clutch force trajectories are analyzed based on engagement performance which can be incorporated in automated manual clutch system. A driveline of a vehicle is modeled using multi body dynamics software and simulation were carried out for different type of force trajectories i.e. linear, parabolic and spline, which is followed by clutch force during engagement. The results of simulation were used to analyze the quality of clutch engagement and vehicle performance by looking into clutch lock-up phase and vehicle launch. The clutch lock time and clutch lock speed for various types of trajectories were calculated and compared. These results were also compared with analytical results reported by researchers. The results would be useful in selecting appropriate type of clutch actuating force trajectories for automation of clutch system of automobiles.

Statistical prediction of the reliability of composite materials with dispersive inclusions

An algorithm for the reliability (probability of failure) calculating of composite materials with stochastically distributed dispersive inclusions under conditions of a complex stress state is proposed. The deterministic composite failure criterion of a Coulomb friction with clutch type is considered. The distribution function of the composite failure loading is obtained, which is the basis for writing the statistical characteristics of materials strength and reliability. The diagrams of the applied loading dependence on the probability of failure of a flat composite sample with different structural heterogeneity of the material and numbers of inclusions are calculated and constructed

Multiple Paternity Benefits Female Marbled Salamanders by Increasing Survival of Progeny to Metamorphosis

AbstractMultiple paternity occurs in most species and animal groups that have been studied. Because mating involves fitness costs to individual females, theory predicts that polyandrous females gain greater fitness benefits than costs, allowing the behavior to be maintained. Genetic, rather than material, benefits often occur in species where males provide females with little more than sperm and seminal fluid. We compared fitness correlates of single‐ and double‐sire clutches from female marbled salamanders (Ambystoma opacum) at the egg, hatchling, and metamorph stages of offspring development. Because clutches were collected from experimental breeding groups, strict paternity exclusion of offspring using microsatellite data allowed us to categorize each clutch as having either one or two fathers. Early offspring viability and size of hatchlings were not different between single‐ and multiple‐paternity clutches. Larvae from the two clutch types were allowed to develop together in field enclosures until metamorphosis. Although there was no difference in size at metamorphosis, survival to metamorphosis was significantly higher in multiple‐paternity clutches (44% vs. 40%) suggesting a benefit for females. The results were consistent with genetic benefits, although maternal effects could not be ruled out. The data did not support predictions of the genetic bet‐hedging and good sperm hypotheses for genetic benefits of polyandry.

An improved startup mode using clutch coupling for in-wheel electric vehicle drives

ABSTRACTBy introducing a new type of clutch into the driveline system of an in-wheel drive electric vehicle, a flexible connection has been developed to replace the rigid one between the hub and the motor. The driving motor can realize variable idling, unlike the internal combustion engine, which needs a minimum rotational speed. This paper proposes a new startup method that utilizes the initial kinetic energy of the motor to achieve a smooth and fast acceleration of the wheel speed from zero to the expected motor speed. First, the powertrain system, including the driving motor, the clutch and the vehicle resistance, is modelled. Second, factors influencing the starting current and the jerk level during the starting process are investigated. In consequence, the idle speed can be interpreted as a tunable variable that determines the tradeoff between the torque capacity and the jerk level. Finally, simulation and experiments on a laboratory test rig are performed. The results validate that the proposed variable-idle speed control strategy has a lower jerk level and lower starting current when compared with those using a direct start under the same load condition.