Frictional Heat Production Research Articles

Development and wear resistivity performance of SiC and TiB2 particles reinforced novel aluminium matrix composites

The aerospace and automotive industries, in particular, rely heavily on aluminium matrix composites because of their exceptional strength-to-mass ratio and resistance to high temperatures. This study investigates the development and wear resistivity performance of Aluminium Matrix Composites (AMCs) reinforced with SiC and TiB2 particles. The experimental work involved fabricating AMCs using Aluminium Alloy 7075 as the matrix material with varying weight percentages of SiC and TiB2 reinforcements. Tribological tests were conducted under different conditions of applied load, sliding speed, and sliding distance to analyze the wear behavior of the composites. Results revealed that higher weight percentages of reinforcement led to lower wear rates, particularly at elevated sliding speeds. X-ray diffraction analysis confirmed the presence of SiC and TiB2 particles in the composites. It is observed that greater applied loads caused greater wear rates, bigger grooves, and substantial frictional heat production, demonstrating a direct relationship between load weight and wear performance. The study indicated that sticky wear management lowered wear rates at longer sliding distances not abrasive wear at shorter distances. The significance of this study lies in its contribution to optimizing the composition of multi-phase reinforced AMCs for enhanced wear resistance in various industrial applications.

Effect of different friction coefficient models on numerical simulation of inertia friction welding of 2219 Al alloy to 304 stainless steel

In inertia friction welding (IFW) of Al alloy to steel, the friction coefficient of interface influences the friction heat production and determines the accuracy of the numerical simulation of welding process. A fully coupled three-dimensional model was established to simulate the IFW process of 2219 Al alloy to 304 stainless steel. By taking different simplifications in the influencing factors (i.e., temperature, sliding velocity, and pressure) of friction coefficient, three types of friction coefficient models were established and utilized in the simulation of IFW process. The strain compensated Arrhenius and Johnson-Cook models were employed to describe the deformation behavior of Al alloy and steel, respectively. Both Al alloy and steel were assumed to be the elastic-plastic body, and the friction stress was calculated by the Coulomb friction model. The friction interface temperature, angular velocity attenuation, axial shortening distance, and joint appearance were measured to verify and compare the accuracy of the established models. The temperature and stress evolutions during the IFW process were also analyzed. With the smallest error in validation, the friction coefficient model, which was a function of temperature, sliding rate, and pressure, showed the best accuracy in describing the friction behavior. By considering the effect of pressure, a more accurate shear stress at the center region of the interface was calculated with a lower value. It means that the friction resistance at the region was lower, promoting the flow of internal Al alloy and the formation of curly-shape flash.

Coupled Thermo-Structural Analysis Model of Solid Rocket Motor Nozzle considering the Variation of Friction Coefficient under Operating Conditions

Multi-interface is a typical feature of solid rocket motor nozzles, and the interface evolution law is an important aspect to analyze the thermo-structural response of solid rocket motor nozzles. In this paper, based on the friction coefficient test at different temperatures, a coupled thermo-structural analysis model of solid rocket motor nozzle considering the variation of friction coefficient under operating conditions was established. Firstly, the friction coefficient was tested to model the variation at different temperatures. Then, by adopting structure gap, variable friction coefficient, thermal contact resistance, and friction heat production, a strongly coupled non-linear model was established. Simulations using the non-linear model and traditional model were performed, in which the stress of the throat insert was within the required stress range of the material. The ground firing test result demonstrated the validity of the analysis model, and the non-linear model was in a better agreement with the firing test than the traditional model. Therefore, it can be concluded that with a more specific friction coefficient to represent the friction behaviour of the different parts of the nozzle, the strongly coupled non-linear model established in this paper can reflect the essence of thermo-structural response of solid rocket motor nozzle.

Study on horizontal wellbore flow of supercritical carbon dioxide drilling

The filter loss in the long open hole interval is considerable during horizontal well drilling utilizing SC-CO2, which affects the wellbore temperature and pressure distribution. In this study, a wellbore flow and heat transfer model that considers fluid filtration characteristics, viscous friction heat production and CO2 physical properties is developed. The temperature and pressure are coupled using an alternating direction iterative method and the flow behavior of SC-CO2 in a horizontal wellbore is analyzed in detail. The results indicate that the mass flow rate loss factor can reach 12.33% at a well depth of 5000 m, but the CO2 leak-off has little influence on wellbore temperature–pressure distribution. In addition, phase transition occurs both in the drill pipe and the annulus during CO2 circulation, and wellbore pressure–temperature conditions are highly related to CO2 physical properties. The operating parameters affect the whole wellbore pressure level; however, they have little effect on the temperature of horizontal interval. Furthermore, the annulus pressure level and the open hole length of horizontal interval are major factors affecting CO2 leak-off. The model can help set the optimum drilling parameters during the actual SC-CO2 drilling process to effectively promote the technology.

Mechanical strength enhancement of ultrasonic metal welded Cu/Cu joint by Cu nanoparticles interlayer

A sound ultrasonic metal welded Cu/Cu joint was obtained via the addition of copper nanoparticles (Cu NPs) interlayer. Cu NPs, synthesized through simple routes, had an average diameter of 45 nm. Hard Cu NPs were conductive to enhance the quantity of friction heat production and activate the surface of base metal, leading to the formation of more effective welded areas. The peak T-peel failure load of the Cu/Cu joint with Cu NPs interlayer was 281.4 N, which was 17.9% higher than that (238.6 N) of the Cu/Cu joint without Cu NPs interlayer. Moreover, due to the addition of Cu NPs interlayer between the Cu sheets, scratched regions in the fracture surface disappeared.

Thermal-Mechanical Coupling Finite Element Simulation and Experimental Study of Disk Brake Friction Pair

This article mainly aims at the study of dry disc brake friction pair thermal-mechanical coupling. Through the calculation of heat source model, the mechanism of produce heat and friction heat production are obtained. Through the study of rough surface contact theory, the contact thermal resistance model of contact surface is established. The distribution of braking energy in two planes is calculated by working condition of tracked vehicle. An abaqus finite element analysis model is established under the influence of rough surface contact thermal resistance on friction pair. It is compared with the traditional finite element simulation. The second heat source heat distribution is considered in new model. The more accurate calculation results can be obtained by consideration of surface thermal resistance effect in thermal-mechanical coupling simulation. In this way, the temperature distribution of the riveted friction pair is obtained. The accuracy of the finite element model is verified by the brake bench test, which provides a meaningful reference for the design of the heat resistance of the brake.

Deductive inference on the plate height equation of ultra performance liquid chromatography

In recent years, separation and analysis workers have made considerable progress on ultra performance liquid chromatography (UPLC). A lot of separation works have been completed which have never been done before. But the theory about chromatographic dynamics of UPLC from the beginning up to now, is remaining in 1950's. Some people explain the principle of UPLC by the van Deemter equation, but this is not right. In this paper, the dynamic process of UPLC has been studied. According to the chromatographic dynamics principle and starting from the heat conduction equation, the plate height equation of UPLC including the influence of mobile phase friction heat production has been deduced as follows: [Formula: see text]. The last item on the right represents the contribution of mobile phase friction heat. When the linear velocity of mobile phase is lower, the contribution of mobile phase friction heat tending to become zero, the plate height equation is reduced to the Horvath and Lin equation. When the linear velocity of mobile phase is high, the temperature difference between the column axial center and edge is directly proportional to the mobile phase linear speed square, and the contribution of thermal effect will largely increased. In this paper, the author clearly pointed out that the column efficiency of UPLC has a direct bearing on the column diameter. Using fine diameter column is helpful to implement column efficiency. Too high mobile phase velocity will lead to the column efficiency collapsed.

Re-evaluation of temperature at the updip limit of locked portion of Nankai megasplay inferred from IODP Site C0002 temperature observatory

In 2010, the first long-term borehole monitoring system was deployed at approximately 900 m below the sea floor (mbsf) and was assumed to be situated above the updip limit of the seismogenic zone in the Nankai Trough off Kumano (Site C0002). Four temperature records show that the effect of drilling diminished in less than 2 years. Based on in situ temperatures and thermal conductivities measured on core samples, the temperature measurements and heat flow at 900 mbsf are estimated to be 37.9°C and 56 ± 1 mW/m2, respectively. This heat flow value is in excellent agreement with that from the shallow borehole temperature corrected for rapid sedimentation in the Kumano Basin. We use these values in the present study to extrapolate the temperature below 900 mbsf for a megasplay fault at approximately 5,200 mbsf and a plate boundary fault at approximately 7,000 mbsf. To extrapolate the temperature downward, we use logging-while-drilling (LWD) bit resistivity data as a proxy for porosity and estimate thermal conductivity from this porosity using a geometrical mean model. The one-dimensional (1-D) thermal conduction model used for the extrapolation includes radioactive heat and frictional heat production at the plate boundary fault. The estimated temperature at the megasplay ranges from 132°C to 149°C, depending on the assumed thermal conductivity and radioactive heat production values. These values are significantly higher, by up to 40°C, than some of previous two-dimensional (2-D) numerical model predictions that can account for the high heat flow seaward of the deformation front, including a hydrothermal circulation within the subducted igneous oceanic crust. However, our results are in good agreement with those of the 2-D model, which does not include the advection cooling effect. The results imply that 2-D geometrical effects as well as the influence of the advective cooling may be critical and should be evaluated more quantitatively. Revision of 2-D simulation by introducing our new boundary conditions (37.9°C of in situ temperature at 900 mbsf and approximately 56 mW/m2 heat flow) will be essential. Ultimately, in situ temperature measurements at the megasplay fault are required to understand seismogenesis in the Nankai subduction zone.

Friction heat production and atom diffusion behaviors during Mg-Ti rotating friction welding process

An innovative physical simulation apparatus, including high speed camera, red thermal imaging system, and mechanical quantity sensor, was used to investigate the friction heat generation and atom diffusion behavior during Mg-Ti friction welding process. The results show that the friction coefficient mainly experiences two steady stages. The first steady stage corresponds to the Coulomb friction with material abrasion. The second steady stage corresponds to the stick friction with fully plastic flow. Moreover, the increasing rates of axial displacement, temperature and friction coefficient are obviously enhanced with the increase of rotation speed and axial pressure. It can also be found that the there exists rapid diffusion phenomenon in the Mg-Ti friction welding system. The large deformation activated diffusion coefficient is about 105 higher than that activated by thermal.

Nonstationary frictional heat production in the course of sliding of a composite layer over the surface of a half space

We obtain the analytic solution of a nonstationary thermal problem of friction for a system formed by a composite plane-parallel layer and a homogeneous semiinfinite base. The layer slides over the surface of the base with a constant velocity. Due to the action of friction forces, the bodies are heated. In the course of interaction, convective heat transfer with the environment takes place on the outer surface of the layer. For the rectangular shape of the cross section of composite fibers, we study the influence of the thermal properties of the materials of the fiber and the matrix on the distribution of temperature in the tribosystem.

A Macro-Micro Coupled Simulation of Positive and Negative Extrusion for Cardan

The cardan belong to dial the fork kind parts, its forming is difficult and forming high quality requirements. Establish macro-micro coupling, and a simulation model for the cardan negative extrusion forming process, a numerical simulation considering the deformation and heat conduction, deformation heat production, friction heat production, dynamic recrystallization and so on many factors. Analyze the deformation process detection cardan anti extruded deformation in advance and is extruded deformation. Meanwhile analysis showed that the cardan forgings have internal 59.929% area completely modification, have 4.7944% area did not happen dynamic recrystallization and didn't get forging modification, and forecasts the cardan internal grain size and distribution, the micro analysis for the prediction of forgings performance and design heat treatment process, provides the basis.

Calculating basal thermal zones beneath the Antarctic ice sheet

AbstractA procedure is presented for using a simple flowline model to calculate the fraction of the bed that is thawed beneath present-day ice sheets, and therefore for mapping thawed, frozen, melting and freezing basal thermal zones. The procedure is based on the proposition, easily demonstrated, that variations in surface slope along ice flowlines are due primarily to variations in bed topography and ice–bed coupling, where ice–bed coupling for sheet flow is represented by the basal thawed fraction. This procedure is then applied to the central flowlines of flow bands on the Antarctic ice sheet where accumulation rates, surface elevations and bed topography are mapped with sufficient accuracy, and where sheet flow rather than stream flow prevails.In East Antarctica, the usual condition is a low thawed fraction in subglacial highlands, but a high thawed fraction in subglacial basins and where ice converges on ice streams. This is consistent with a greater depression of the basal melting temperature and a slower rate of conducting basal heat to the surface where ice is thick, and greater basal frictional heat production where ice flow is fast, as expected for steady-state flow. This correlation is reduced or even reversed where steady-state flow has been disrupted recently, notably where ice-stream surges produced the Dibble and Dalton Iceberg Tongues, both of which are now stagnating.In West Antarctica, for ice draining into the Pine Island Bay polynya of the Amundsen Sea, the basal thawed fraction is consistent with a prolonged and ongoing surge of Pine Island Glacier and with a recently initiated surge of Thwaites Glacier. For ice draining into the Ross Ice Shelf, long ice streams extend nearly to the West Antarctic ice divide. Over the rugged bed topography near the ice divide, no correlation consistent with steady-state sheet flow exists between ice thickness and the basal thawed fraction. The bed is wholly thawed beneath ice streams, even where stream flow is slow. This is consistent with ongoing gravitational collapse of ice entering the Ross Sea embayment and with unstable flow in the ice streams.

The quasisteady contact problem of thermoelasticity for a two-layered cylinder under frictional heating and nonideal thermal contact

In this article we give an analytic solution of the polar-symmetric quasisteady thermoelastic contact problem for a two-layer hollow circular cylinder. The problem is solved taking account of frictional heat production and thermal resistance on the mutually tangent surfaces of the components of the cylinder. On the exterior boundary of the two-layer system we study the condition of Winkler elastic fixing. In the solution we apply the Laplace transform with respect to time. We carry out a numerical analysis whose results are shown as graphs.

Stress Field at a Transcurrent Plate Boundary in the Presence of Frictional Heat Production at Depth

—A model is proposed to study the modification of the stress field at a transcurrent plate boundary due to frictional heat production at depth. Two cases are considered a stable and a stretched lithosphere. The model is applied to those weak faults where the dynamic friction is small compared to a static one; if the deformation along the brittle portion of the fault is entirely accommodated by a series of seismic ruptures in a quasi-static state where the fault has been moving for millions of years, the long-term thermal field perturbation due to these ruptures results in only a few degrees and can be neglected. The boundary zone is considered as a viscoelastic body subject to a constant strain rate. The lower section of the boundary is assumed to slip aseismically along a vertical transcurrent fault and to completely accommodate the plate motion, while the upper section is locked. The slipping zone is divided into a semi-brittle zone, placed between the isothermal surfaces of 300°C and 450°C, and a ductile zone beneath. The frictional heat is calculated by assuming a linearly decreasing friction in the semi-brittle and a constant friction in the ductile zones. The heat modifies the temperature field, producing an upward movement of the semi-brittle and ductile fault sections. As a consequence, the thickness of the brittle fault section is reduced and friction at the base of this section is less. The stress field in the boundary zone is calculated as a function of time for different friction profiles and slip rates on the fault. Owing to heat production, a greater stress concentration is produced on the brittle fault section, while shear stress is lowered in regions occupied by the uplifted semi-brittle layer. These effects are found to be remarkable only in the case of a stable zone, with a standard unperturbed geotherm, while they are irrelevant in a stretched zone with a high geothermal gradient. In any case, the role of the semi-brittle layer appears to be more prominent in the case of boundaries with higher slip rates, due to the presence of higher stress values.

Convergent flow of ice within the Astrolabe subglacial basin, Trre Ad�lie, East Antarctica: an hypothesis derived from nummerical modelling experiments

The existence of a large subglacial lake beneath the antarctic Ice Sheet at Terre Adelie indicates the presence of basal ice at its pressure-melting temperature. A numerical model of the ice-sheet thermal regime is employed using the balance velocity of the ice sheet as an initial model input in order to calculate ice-sheet basal temperatures. However, the results from this model show the Terre Adelie area to be characterised by basal freezing. Heat in addition to that accounted for in the model is thus required at the ice-sheet base in order for pressure melting temperatures to be attained. The sources for such heat are (1) an enhanced geothermal heat flux and (2) an increase in frictional heating caused by the flow of ice. In this paper the latter possibility is expanded by hypothesising that subglacial topography induces convergent ice flow around Terre Adelie, causing enhanced basal ice velocities. Model experiments indicate that an increase in ice velocity (from 7 to at least 42 m yr?1) is required to raise the temperature of the basal ice to the pressure melting value. Increased ice velocity, and consequent frictional heat production due to convergent ice flow, may therefore be important in explaining the location of the subglacial lake in this region. These results allow the process of convergent ice flow within a contemporary ice sheet to be quantified. A verification (or otherwise) of the model results may be possible if ice surface velocity measurements from modem GPS methods are made.

Convergent flow of ice within the Astrolabe subglacial basin, Terre Adélie, East Antarctica: an hypothesis derived from numerical modelling experiments

The existence of a large subglacial lake beneath the antarctic Ice Sheet at Terre Adélie indicates the presence of basal ice at its pressure-melting temperature. A numerical model of the ice-sheet thermal regime is employed using the balance velocity of the ice sheet as an initial model input in order to calculate ice-sheet basal temperatures. However, the results from this model show the Terre Adélie area to be characterised by basal freezing. Heat in addition to that accounted for in the model is thus required at the ice-sheet base in order for pressure melting temperatures to be attained. The sources for such heat are (1) an enhanced geothermal heat flux and (2) an increase in frictional heating caused by the flow of ice. In this paper the latter possibility is expanded by hypothesising that subglacial topography induces convergent ice flow around Terre Adélie, causing enhanced basal ice velocities. Model experiments indicate that an increase in ice velocity (from 7 to at least 42 m yr?1) is required to raise the temperature of the basal ice to the pressure melting value. Increased ice velocity, and consequent frictional heat production due to convergent ice flow, may therefore be important in explaining the location of the subglacial lake in this region. These results allow the process of convergent ice flow within a contemporary ice sheet to be quantified. A verification (or otherwise) of the model results may be possible if ice surface velocity measurements from modem GPS methods are made.

Seismicity and stress rotation in a granular model of the brittle crust

THE basic mechanical process responsible for earthquakes and faulting is not known. The intuitive notion of frictional slip on faults between elastic crustal blocks cannot be reconciled with laboratory measurements of the strength of rocks1, field observations of heat flow2,3 and stress orientation4 around the San Andreas fault in California, and seismological estimates of the energy radiated by earthquakes5. The weakening of large faults by elevated pore-fluid pressure6 has been suggested as one solution to this paradox, but places severe constraints on the hydrological conditions of the faults concerned. Here I propose an alternative model for earthquake mechanics, in which the crust is treated as a system of many interlocking blocks divided by many faults7. The model combines this random granular structure with simple, deterministic mechanical interactions. Numerical simulations of the deformation of an aggregate of rough grains under compressive stress show earthquake-like elastodynamic failures without frictional heat production, and substantial rotation of stresses across shear zones, which mimics field observations. There remain problems of scale in comparing these simulations with nature, but a seismological test of the model may be possible.

Effects of subduction parameters on geothermal gradients in forearcs, with an application to Franciscan Subduction in California

Geothermal gradients in forearcs are often suppressed below normal values because of the cooling effect of the relatively cold downgoing plate. In this paper, finite difference thermal modeling is used to evaluate the influence on forearc gradients of variations in six potentially important subduction zone parameters. Variations in forearc radiogenic heat production over the general range likely in forearc rocks (0 to 1.5 × 10−6 W m−3) cause only minor changes in temperatures at the base of the forearc (about 2 to 35%, depending on other parameters) and thus have relatively little effect on pressure‐temperature (PT) conditions of metamorphism. However, their effect on gradients at shallow levels and thus on surface heat flows may be greater (up to about 100%). Likely variations in forearc thermal conductivity (1.5 to 3.5 W m−1 °C−1) similarly change temperatures at the base of the forearc only modestly (10–25%) but change surface heat flows more substantially (1.45–1.75 times). Decreasing the subduction angle from 27° to 3.6° increases gradients by about a factor of 2 at both deep and shallow levels. Decreasing the subduction rate by a factor of 8 (160 to 20 km/m.y.) increases gradients by about a factor of 2 when frictional heating at the plate contact is excluded, and less when modest amounts of frictional heating are included. Forearc gradients increase virtually linearly with the presubduction geothermal gradient in the subducting slab and thus are higher above a younger slab. When frictional heating is excluded, forearc gradients are 2.0–2.8 times higher above a 10 m.y. old slab than above a 150 m.y. old slab. Again, the relative effect is lessened when frictional heating is incorporated. The amount of frictional heating at the plate contact potentially has the greatest influence on forearc gradients. The frictional heat production, h, is given by h = τ Vs, where τ is the shear stress along the plate contact and VS is the subduction rate. The modeling shows that forearc gradients increase linearly with τ. Unless plate contact shear stresses are only a small fraction of those expected with frictional sliding of dry rocks, outer parts of forearcs would be the sites of pervasive low‐P/T metamorphism (greenschist facies) rather than high‐P/T metamorphism (blueschist facies). Very high fluid pressures along the plate contact are probably the way shear stresses are reduced. Pressure‐temperature conditions of blueschist‐facies metamorphism in the Franciscan subduction complex of California are easily explained with typical subduction rates and slab ages with plate contact shear stresses of the order of 10 MPa (equivalent to around 3% of lithostatic pressure), but stresses within the range zero to a few tens of megapascals are probably permitted by the thermal constraints. Speculative application of the modeling results assuming a shear stress of 4% of lithostatic pressure to plate motion reconstructions for the Franciscan forearc suggests that forearc gradients were about 8°C/km around 85 Ma when the subducting slab was perhaps 145 m.y. old and the subduction rate was perhaps 95 km/m.y. Gradients increased moderately through the latest Cretaceous to middle Tertiary as subduction became slower and the subducting slab became younger, reaching about 16°C/km at 28 Ma when the slab age was about 11 m.y. and the subduction rate was about 48 km/m.y. The slab age, subduction rate, and forearc gradient then remained fairly constant until 5 Ma, when subduction slowed to about 32 km/m.y. and the slab age decreased to about 8 m.y., causing gradients to rise to about 20°C/km.

A contact problem for a thick layer showing wear and heat production

A contact problem is considered and solved in thermoelasticity for a thick layer, which incorporates the surface microgeometry, wear, and frictional heat production. The treatment is reduced to a system of nonlinear integral equations, which is solved by successive approximation. Some new results are obtained.

Frictional heating and pore pressure rise due to a fault slip

Summary. Accurate estimation of frictional stress is crucial to determining the bounds of pre- and post-earthquake states of stress. A long-term average value of 10 MPa, deduced from heat flow data in the San Andreas fault zone, is frequently cited, but it may or may not represent the resistive stress of an individual slip event. Based on 1-D modelling, this paper deals with frictional heating, pore pressure rise, and migration of fluid, and speculates upon their consequences for triggering of earthquakes and emission of earthquake light. Analytic solutions are obtained for temperature and pore pressure rises due to frictional heating. Results are obtained for three heating models: 1, instantaneous heating; 11, constant heating rate; and 111, heating rate proportional to inverse square root of time. For the same total heat generation and physical parameters, solutions indicate that, for times less than twice the slip duration or distances with two thermal diffusion distances, temperature and pressure distributions are sensitive to heating models; at greater times and distances, they are insensitive to models. Though temperature rise due to I-m slip under 10MPa frictional stress may reach 200K or more on the slip surface, the rise is not measurable in practice at a distance beyond about 10 m from the slip surface. Estimates of pore pressure rise (0.2-2MPa) depends crucially upon permeability and slip duration. Darcy flow may exceed lO-'m s-' at one thermal diffusion distance; and immediately after the slip ends, reverse flow towards slip surface develops. Because the pore pressure front can advance beyond the temperature front by 100-1000 times, measurement of pore pressure variation is an alternative to temperature measurement for estimating frictional stress. A rise of 500Pa is measurable at 330m within 30 days for a fault slip with frictional heat production of 10MJm-2. It is speculated that the propagating pressure front created by an initial slip, rather than the fluid flow itself, may weaken the frictional strength elsewhere and lead to additional minor slips and perhaps a larger earthquake. With large frictional stress and displacement, heating may also