Friction Pads Research Articles

Experimental Investigation on the Friction and Wear Characteristics of Palm Seed Powder Reinforced Brake Pad Friction Composites

In this research work, palm seed power (0–9 wt%, step of 3%; four composites sample, namely P0, P3. P6, P9) were used to reinforce master batch of friction composite materials containing phenolic resin binder, steel swarf fibre, cashew, alumina, graphite, copper and zinc. The fabrications were as per standard industrial practice via hot compression moulding route. Thereafter, samples were cut and characterized for their tribological characteristics on specifically designed braking dynamometer using grey cast iron disc as per TS 555 and TS 9076 standards. Physical and mechanical properties such as hardness and density of the samples were also determined. Further, multi-criteria-decision-making like Preference Selection Index methods are used to ascertain ranking of material alternatives based on performance criteria. Both the subjective analysis and PSI output are in agreement with each other. Hence, such techniques often found suitable for decision-making or ranking of materials alternatives when performance criteria are of conflicting in nature.

Planar arrangement of permanent magnets in design of a magneto-solid damper by finite element method

This article studies the energy dissipation mechanism of a proposed magneto-solid damper using a three-dimensional finite element model developed in COMSOL Multiphysics software. The energy dissipation mechanism of the magneto-solid damper dissipates energy through combined actions of friction and eddy current damping. The key components of the magneto-solid damper are a steel plate, two copper plates placed on two sides of the steel plate in parallel, and two planar arrays of permanent magnets each one placed between the steel plate and one of the copper plates. These arrays are kept away from the steel and copper plates through narrow gaps; the gaps between them and the steel plate are filled with thin friction pads made of non-magnetic materials. The attractive magnetic interaction between the permanent magnet arrays and the steel plate provides the normal force for the friction developed between the friction pads and the steel plate when the permanent magnet arrays move relative to the steel plate. The motion of the permanent magnet arrays relative to the copper plates, on the other hand, provides the eddy current damping. The main contribution of this article is to optimize the pole arrangement of the permanent magnets and demonstrate that how the optimum pole arrangement can affect the energy dissipation capacity of the magneto-solid damper. The analysis results show that, for a given number and size of the permanent magnets, alternate arrangement of the poles of permanent magnets along the direction of their motion is the most optimal case resulting in large and smooth hysteresis force–displacement loops. This pole arrangement has also been used to find the optimum size of the steel and copper plates by addressing edge and skin effects in the design of the damper.

Maximizing Friction by Passive Jamming

AbstractMany solutions for getting grip on varying substrates exist in nature and in technical applications, but they fail on substrate geometries they are not specifically designed for. A novel passive load‐dependent system is developed that creates high friction forces on a large variety of substrates: the granular media friction pad. With an elastic membrane encasing granular media, it reversibly undergoes the jamming transition only by varying the normal load. Here, the friction performance on different substrates is shown and the underlying physical mechanisms in a numerical simulation are investigated.

Seismic design and behavior of self-centering energy dissipation braced steel frame

A self-centering energy dissipation (SCED) brace that utilized disc springs to provide self-centering capability and friction pads to dissipate energy was developed. Based on Bouc–Wen model and the working principle of SCED brace, a restoring force model is developed to describe the mechanical behavior of the brace. Comparisons between the cyclic loading tests and predicted results are conducted. Results show that the restoring force model can accurately predict both the energy dissipation and self-centering capabilities of SCED brace. A performance-based design method for frame structures with SCED braces is developed corresponding to the four-level seismic fortification objective, that is, no damage under minor and moderate earthquakes, replaceable or repairable under major earthquakes, and no collapse under mega earthquakes. A typical SCED braced steel frame was designed, and nonlinear time-history analysis was conducted to analyze the seismic performance and resilience of the braced frame. It is demonstrated that the SCED braced frame has superior resilience with small residual deformation under the moderate and major earthquakes due to the self-centering capability provided by the SCED brace. The collapse of the structure is also effectively avoided due to the stable energy dissipation and lateral stiffness provided by the SCED brace.

Experimental investigation of a self‐centering precast concrete beam‐to‐column connection with top and bottom friction energy dissipaters

SummaryThe new friction material, non‐asbestos organic, and Belleville springs are applied to the friction energy dissipaters (FEDs) to improve its friction performance. The new high‐performance FEDs are placed in the top and bottom parts of the self‐centering precast concrete (SCPC) beam‐to‐column connections, which have inherently reduced residual deformation caused by posttensioned tendons, to enhance energy dissipation efficiency. Besides, the reasonable design of the connection between FEDs and backbone members makes it easy for the disassembly of all members, which significantly enhances the repair efficiency after a major earthquake. Theoretical analyses and 14 tests were performed on a full‐scale specimen, which were assembled two times, and the friction pads were replaced one time, to investigate the effects of various parameters on the performance of such FED‐SCPC beam‐to‐column connections. The influence of key design parameters on the hysteretic behaviors, such as stiffness, loss of posttensioned tendons force, self‐centering capacity, and energy dissipation capacity, has been analyzed. The test results indicate that the FED‐SCPC beam‐to‐column connections can achieve significant and reliable energy dissipation levels while maintaining self‐centering capabilities. The experimental and theoretical results can provide certain references for the seismic design and assembly of such structures.

Application of hybrid AHP-TOPSIS technique in analyzing the braking performance sensitivity of organic-ceramic fibrous reinforced friction composites

In this research work, brake pad friction composite materials based on binary and ternary combinations of ceramic-organic fibres have been realized, following evaluation of braking performance parameters on Krauss friction testing machine adopting ECE R-90 regulations and PVW-32 standard test protocol. The obtained experimental performance data has been further used for the assessment of performance based ranking using hybrid AHP-TOPSIS technique. The order of relative weights or priority order of performance defining criteria as obtained by AHP is μ-Performance (μp) ~ Stability Coefficient (α) > % μ-Recovery > Wear (g) > % μ-Fade > DTR (°C) > Friction Fluctuations (Δμ) > Variability Coefficient (γ). The consistency verification highlights that λmax = 8.0391, consistency index = 0.0045579, and consistency ratio (CR) = 0.00323 << 0.1 (upper bound limit for acceptance of CR). The aramid fibre 5-7.5 wt.% in combination with other fibres 25-22.5 wt.% (for binary combination) and 12.5/12.5 - 11.25/11.25 wt.% (for ternary combinations) has been found to impart the best overall performance level relative to other combos of the friction composites under investigation. The sensitivity analysis of performance defining criteria's and ranking orders of the compositions in the respective formulations gives robust/stable observations as the weights changes from ± (10-20)%. The hybrid AHP-TOPSIS technique in-conjunction-with sensitivity analysis might sever as an effective tool in the decision making whenever there are finite material alternatives and finite performance determining criteria having conflicting nature.

STUDY ON TRIBOLOGICAL CHARACTERISTICS OF HOISTING EQUIPMENT BRAKE SYSTEM

In industrial production, there are strict requirements for the braking effect of heavy transport equipment such as elevator and belt conveyor. The working capacity and reliability of the brake are the basis for ensuring efficient production. Based on the friction and wear test, taking the average friction coefficient and stable wear rate as the key parameters to measure the reliability and stability of the brake, the friction and wear characteristics of the hydraulic disc brake of the hoist under different working conditions are analyzed and studied. The results shows that the average friction coefficient and stable wear rate of the brake fluctuate less with the change of brake pressure in the middle speed range. At this time, the adhesive and matrix fiber in the friction pad have not been decomposed and modified, and the strength and shape of the surface micro convex structure are relatively moderate, so the braking reliability is in good condition.

A Study of the Disc Scoring Generation Principle and Reduction(III)

<div class="section abstract"><div class="htmlview paragraph">In the latest works [12], we presented the guideline for reducing Metal pick up(MPU, the main component of disc scoring) by controlling the location of the roughness of disc, the brake pad friction coefficients and the disc slot's size. In this study, the previously studied iron transfer theory to 'Cu free' brake pad and the disc surface roughness controlling methods which are based on the mass production manufacturing process are applied. It is possible to suggest the ways to improve the scoring-free disc without reducing friction coefficient between the disc and pad, and any demerit such as increased wear and airplane noise like conventional slot discs [11].</div></div>

A Multi-Scale Simulation Approach to Investigate Local Contact Temperatures for Commercial Cu-Full and Cu-Free Brake Pads

Copper from vehicles disc brakes is one main contributor of the total copper found in the environment. Therefore, the U.S. Environmental Protection Agency (EPA) and the automotive industries started the Copper-Free Brake Initiative. The pad friction material is essentially composed of a binder, fillers, reinforcing fibres and frictional additives. Copper and brass fibres are the most commonly used fibres in brake pads. There is a need to understand how the contact temperature distribution will change if copper-based fibres are changed to steel fibres. The aim of this work is, therefore, to investigate how this change could influence the local contact temperatures. This is done by developing a multi-scale simulation approach which combines cellular automaton, finite element analysis (FEA) and computational fluid dynamics (CFD) approaches with outputs from inertia brake dyno bench tests of Cu-full and Cu-free pads. FEA and thermal-CFD are used to set the pressure and the temperature boundary conditions of the cellular automaton. The outputs of dyno tests are used to calibrate FEA and CFD simulations. The results of the study show lower peaks in contact temperature and a more uniform temperature distribution for the Cu-free pad friction material.

THE NEW INERTIA DYNAMOMETER FOR FRICTION AND WEAR TESTING OF BRAKE PADS AND BRAKE DISCS

For the sake of driving safety, the right choice of the brake pad friction material and its manufacturing processes to obtain the appropriate tribological properties is a matter of priority for brake pad manufacturers. Determination of the tribological properties is best done in component tests, i.e. in the setup: brake pads – brake disc. At the request of one of the domestic brake pad manufacturers, as part of the POIR project, an inertia dynamometer for testing friction and wear of brake pads and brake discs was developed and manufactured, which was given the symbol T-33. A test methodology was developed based on the “Cold application section” procedure described in SAE J2522:2003. The T-33 inertia dynamometer is designed for testing brake pads and brake discs intended for five vehicles representing the passenger vehicle class and vans. The paper presents the new test stand, test methodology, and results of verification tests of the T-33 dynamometer (interlaboratory comparison tests) performed on the Cinquecento vehicle brake setup.

Birds land reliably on complex surfaces by adapting their foot-surface interactions upon contact.

Birds land on a wide range of complex surfaces, yet it is unclear how they grasp a perch reliably. Here, we show how Pacific parrotlets exhibit stereotyped leg and wing dynamics regardless of perch diameter and texture, but foot, toe, and claw kinematics become surface-specific upon touchdown. A new dynamic grasping model, which integrates our detailed measurements, reveals how birds stabilize their grasp. They combine predictable toe pad friction with probabilistic friction from their claws, which they drag to find surface asperities-dragging further when they can squeeze less. Remarkably, parrotlet claws can undergo superfast movements, within 1-2 ms, on moderately slippery surfaces to find more secure asperities when necessary. With this strategy, they first ramp up safety margins by squeezing before relaxing their grasp. The model further shows it is advantageous to be small for stable perching when high friction relative to normal force is required because claws can find more usable surface, but this trend reverses when required friction shrinks. This explains how many animals and robots may grasp complex surfaces reliably.

Design of a frictional–electromagnetic compound disk brake for automotives

According to the disadvantages of serious wear and heat fade of friction pad in frequent and high speed braking of friction brakes, and the insufficient power of electromagnetic brakes in low speed braking, a novel frictional-electromagnetic compound disk brake which combines both of these two brake principles is proposed for automotives in this paper. The excitation coils are designed based on the Zhang Yicheng theory model, and the compound brake prototype is manufactured based on the self-made magnetic brake pads and existing automotive brakes. The magnetic field and dynamic of the brake are simulated by using COMSOL Multiphysics software. The frictional–electromagnetic compound brake tests are implemented on the reconstructive disk brake simulation test bench. The experimental results show that the friction braking torque accounts for more than 90% of the compound braking torque in the process of compound braking, and the trend of the change is the same as that of the compound braking torque. When the initial braking speed exceeds 75 km/h, the electromagnetic braking torque does not increase with the increase in speed, instead, it decreases slightly because of demagnetization. The designed frictional–electromagnetic compound disk brake has good braking performance.

Seismic response control of multi-story base-isolated buildings using a smart electromagnetic friction damper with smooth hysteretic behavior

Abstract This paper studies the use of a smart/semi-active electromagnetic friction damper (SEMFD) for the control of seismic response of multi-story base-isolated buildings. The SEMFD consists of a ferromagnetic plate and two similar arrays of thick rectangular ferromagnetic-core coils (FCs) connected in series. The FCs are attached to the two sides of the ferromagnetic plate through two non-magnetic friction pads. The force in the damper is developed because of the friction between the friction pads and the ferromagnetic plate when the FCs moves relative to ferromagnetic plate. The normal force between the friction pad and the ferromagnetic plate is caused by the attractive magnetic interactions between the FCs arrays and the ferromagnetic plate. The magnitude of this force is controlled by a proposed semi-active controller that is capable of varying the current flowing through the FCs in such a way that it is able to avoid stick-slip motion by smoothing the nonlinear hysteretic behavior of the SEMFD. The capability of the SEMFD and the proposed semi-active controller to control the seismic response of base-isolated buildings is demonstrated by implementing them into the dynamic model of a six-story base-isolated building supported on lead-rubber bearings (LRBs). The numerical results show that the SEMFD and its semi-active controller are capable of limiting the displacement of the base floor without noticeably increasing the inter-story drifts and absolute accelerations of the floors. It is demonstrated that the parallel actions of the LRBs and the SEMFD in the base floor create a smart base isolation system that is capable of fully protecting a multi-story building from ground motions with intensities at a level as that of the ASCE 7–10 Maximum Considered Earthquake (MCE).

An Empirical Approach for the Determination of Skin Elasticity: Finger pad Friction against Textured Surfaces

Surface topography significantly influences tactile friction and perception. While friction forces can be reduced by surface texturing, selection of pattern dimensions is challenging due to the highly variable elastic modulus of the skin. This work proposes an empirical approach for the evaluation of the skin elasticity through surface transition from asperity to full contact state. To highlight the contact transition, two textures with evenly distributed identical micro asperities, but varying density, were moulded with several grades of silicone rubber. Dynamic friction coefficient measurements were performed during finger pad sliding against the textured samples with a range of normal loads up to 5 N. A combination of analytical and numerical contact models is used to explain the observed friction behaviour, estimate the development of contact area and calculate the effective elastic modulus of the skin at the micro-scale. Low density textures clearly indicate the transition to the full contact state, which is reflected in friction coefficient development, while high density textures remain in an asperity contact state, with significantly lower friction values. The effective Young's modulus is hereby estimated in the range of 0.2–0.5 MPa. Observed frictional behaviour is explained by the change in the apparent and real contact areas. The presented approach allows to study the influence of individual surface parameters on effective skin elastic modulus, which is essential for the development of functional surfaces with improved tactile perception.

Treefrog Toe Pad‐Inspired Micropatterning for High‐Power Triboelectric Nanogenerator

AbstractInspired by treefrog's toe pads that show superior frictional properties, herein, an industrially compatible approach is reported to make an efficient dielectric tribosurface design using customizable nonclose‐packed microbead arrays, mimicking the friction pads of treefrogs, in order to significantly enhance electrification performance and reliability of triboelectric nanogenerator (TENG). The approach involves using an engineering polymer to prepare a highly ordered large‐area concave film, and subsequently the molding of a convex patterned triboreplica in which the concave film is exploited as a reusable master mold. A nature‐inspired TENG based on the patterned polydimethylsiloxane (PDMS) paired with flat aluminum (Al) can generate a relatively high power density of 8.1 W m−2 even if a very small force of ≈6.5 N is applied. Moreover, the convex patterned PDMS‐based TENG possesses exceptional durability and reliability over 25 000 cycles of contact–separation. Considering the significant improvements in power generation of TENG; particularly at very small force, together with cost‐effectiveness and possibility of mass production, the present methodology may pave the way for large‐scale blue energy harvesting and commercialization of TENGs for many practical applications.

Determination of the Maximum Temperature of the Friction Pad in a One-Disk Clutch

We obtain the exact solution of the thermal problem of friction for a one-disk clutch with regard for the power law of variation of the friction torque with time. The evolution of the angular velocity, specific friction power, and temperature is investigated. The engineering formulas are proposed for finding the maximum temperature, the time of its attainment, and the duration of heating of the clutch depending on the parameter that describes the time profile of the friction torque. It is shown that the obtained analytic results are in good agreement with the available numerical solutions.

Optimization preventive maintenance of equipment production on palm oil mill

Maintenance is an important issue that must be considered, especially in the agroindustry company. This paper is to identify and prioritize the most critical component in the production of palm oil using FMEA, and schedule maintenance with optimal total cost of maintenance. RPN obtained score from the highest to the lowest to be scheduled maintenance that is a component of the worm screw press machine, V-belt thresher drum equipment, V-belt separator clarification equipment, steel cable sling tracklier equipment, door seals equipment sterilizer, wheel lorry with ad on lorry equipment, V-belt boiler, screw pn clarification separator equipment, friction pad clarification separator equipment and V-belt equipment at the seed stasion. Optimization of the total cost of maintenance is the reliability level of 90% at a cost Rp. 131.443.940,2/year. Scheduling maintenance can save as much as 47,4% compared to no maintenance scheduling.

Effect of silane surface treatment on the physico-mechanical properties of shell powder reinforced epoxy modified phenolic friction composite

Physico-mechanical performance of the epoxy modified phenolic friction composite reinforced with silane surface treated crab, periwinkle, and scallop shell powders were evaluated based on Extension Evaluation Method (EEM). The shell powders were silane surface treated and their morphologies and thermal behaviors were studied using a Scanning Electron Microscope (SEM) and thermo-gravimetric analyzer. SEM morphology shows that the scallop shell powders are finer then the periwinkle and crab shell powders which played a major role in enhancing the surface and physico-mechanical properties of the scallop shell powders and its friction pads. Thermal analysis indicates that the untreated scallop shell powders are most stable thermally. The physico-mechanical properties of the friction composites were studied based on IS 2742 standard. The physico-mechanical and chemical properties observed for the periwinkle and scallop shell based friction composites are well within the recommended values of the OEM and also showed the best results among the chosen fillers. The outcome of this work based on EEM indicates that the silane surface treated scallop shell and periwinkle shell powder could be a potential friction material to be used in brake pads/linings of light and medium duty commercial vehicles.

Braking Efficiency and Stability of Chassis Braking System of Combine Harvester: The Theoretical Derivation and Virtual Prototype Simulation

With the advancement of agricultural mechanization, the safety of agricultural vehicles has aroused extensive concern. However, conventional methods evaluate the performance of the combine harvesters in a laborious and inaccurate filed-test way. It is still a challenge to evaluate their performance in a theoretical derivation-based simulation way. Here, we accurately derive the braking model of the combine harvester, which provides a guidance for further braking simulation. Firstly, a four-wheel braking system was designed and theoretically checked. Secondly, the virtual prototype of the chassis braking system was established in ADAMS, in consideration of the complicated contact characteristics between the tire and the road and between the friction pad and the brake disk. Finally, simulation experiments of braking efficiency and directional stability were carried out under different braking conditions. By this means, we find a novel effective yet simple way to optimize the braking efficiency as well as the sufficient braking stability of combine harvesters. The results show that braking efficiency would be improved with stronger braking force, lower initial braking velocity, and lighter weight of the combine harvester. Compared with straight-line braking, steering braking shows lower braking efficiency and less inclination of rear wheel bounce under the same braking conditions. As for braking directional stability, the lateral slippage would be increased with the locking of rear wheels, higher driving speed, or lower road adhesion coefficient. In addition, the simulation results are in agreement with the theoretical results, proving the validity of the virtual prototype simulation. Overall, other than traditional filed-test methods, our method provides an effective yet simple way for designing and evaluating the chassis braking system of combine harvesters.

Hysteretic behavior and failure mechanism of an assembled self-centering brace

This study proposes a self-centering brace that can be easily assembled. It incorporates disc springs and friction pads to provide recentering force and energy dissipation, respectively. To analyze the hysteretic behavior of the assembled self-centering brace (ASCB), a hysteretic model based on the working mechanism of the ASCB is proposed. A modified Bouc–Wen model is developed to predict the behavior of the brace. A 1.336 m ASCB was designed and fabricated, and its hysteretic behavior was evaluated by cyclic testing. Results shows the full flag-shaped response of the ASCB and confirms the validity of the modified Bouc–Wen model. Fatigue and destructive tests verifies the stability of recentering and energy dissipation behaviors under cyclic loading with large axial deformation. After 50 cyclic loadings with an axial deformation ratio of 1.1%, the hysteretic behavior of the brace is stable, and the change in the maximum axial force is less than 4.2%. When the loading deformation ratio exceeds 2.0%, the brace fails because of overall buckling.