Tiago Cousseau

• PhD
• Professor at Federal University of Technology of Paraná

This study investigates the influence of idler roller diameter on indentation rolling resistance and idler rotating resistance in belt conveying systems, crucial for long-distance bulk material transport. It encompasses the impact on grease-lubricated rolling bearings, grease-filled labyrinth seals, and lip seals, with the aim of optimizing energy...

Ethanol has emerged as a promising alternative to fossil fuels, but its use can lead to significant dilution in lubricants, particularly during cold start or heavy traffic. This dilution can affect the performance of additives, including friction modifiers like molybdenum dithiocarbamate (MoDTC), which are designed to reduce friction under extreme...

Aftermarket additives are used to enhance the performance of internal combustion engines in specific aspects such as reducing wear, increasing power, and improving fuel economy. Despite their advantages, they can sometimes cause corrosion-related problems. This research evaluated the corrosiveness of four aftermarket additives on the corrosion of a...

This research aims to examine the relationship between roughness, film thickness, and friction coefficient in relation to pitting wear resistance during the rolling-sliding contact fatigue of forged and plasma-nitrided gears. In the present work, forged gears in continuous cooling bainitic steel were manufactured and plasma nitrided with three sets...

Metal conditioners (MC) are added to lubricants to enhance their friction and wear in friction pairs, mainly in engines, gearboxes, and rolling bearings. Its growth in the Brazilian market is primarily focused on internal combustion engines. The effect of mixing MC with commercial engine oil (SAE 5W-30 API SN) was studied regarding the rheological...

The urgent need for drastic reduction in emissions due to global warming demands a radical energy transition in transportation. The role of biofuels is fundamental to bridging the current situation towards a clean and sustainable future. In passenger cars, the use of ethanol fuel reduces gas emissions (CO2 and other harmful gases), but can bring tr...

Using greases offers numerous advantages to the railroad system, which include the lifespan extension of wheels and rails, fuel consumption decrease, and the reduction of the friction coefficient and component wear. However, there is still a lack of understanding regarding the relationship between the grease formulation and its performance. This st...

The present investigation aims correlate the roughness, film thickness and friction coefficient with pitting wear resistance along the rolling-sliding contact fatigue of forged and plasma nitrided gears. The hypothesis of this work is that the pitting wear resistance of forged gears can be greatly improved by pulsed plasma nitriding. Weibull’s stat...

Rail grease formulation effect in friction, wear and grease loss due to cen- trifugal force was evaluated through pin on disc and free flow tests. Six greases were fully formulated so that the effects of the thickener and the base oil viscos- ity on grease performance could be isolated, since these greases have the same consistency and additive pac...

Gear manufacturers must make decisions about the manufacturing materials and superficial treatments. The best performance as to a type of failure should be evaluated. However, it is a time-demanding and costly process. The present work proposes a methodology for a comprehensive assessment (experimental and computational) of contact fatigue of gears...

Idler rolls are an integral part of belt conveyors. Recently, steel idler rolls have been replaced with polymeric ones in low to middle load applications, bringing several advantages due to the polymer’s lightweight and low abrasiveness in the conveyor belt. However, using polymeric material for high load application brings challenges, particularly...

Ore conveyor belt rollers operate in harsh environments, making them prone to premature failure. Their service lives are highly dependent on the stress field and bearing misalignment angle, for which limit values are defined in a standard. In this work, an optimization methodology using metamodels based on radial basis functions is implemented to r...

Metal conditioners (MC) are friction, wear, and heat-reducing agents between metal components in motion and are mainly used in engines and transmission boxes as aftermarket additives. Laboratory and field tests were conducted to assess the performance of a commercial MC. Laboratory tribotests revealed the MC's potential to reduce wear and friction...

Samples of AISI 409 were thermochemically treated by the Solution Heat Treatment after Plasma Nitriding (SHTPN) process. SHTPN process consisted of a nitriding step followed by solution annealing at 1100 °C and rapid cooling down to room temperature. The second cycle of quenching (950 or 1050 °C), followed by tempering (250, 450, or 650 °C), was pe...

Tribology is a branch of science that deals with machine elements and their friction, wear, and lubrication. Tribology of Machine Elements - Fundamentals and Applications presents the fundamentals of tribology, with chapters on its applications in engines, metal forming, seals, blasting, sintering, laser texture, biomaterials, and grinding.

This work aims to predict the temperature in the bearing from the thermal modeling of a Rolling bearing. The model isbased on the law of conservation of energy in a transient regime, whose equations are based in the thermal resistancenetwork. In this model, the bearing was discretized at 39 nodes and has major detail in the inner region of the bear...

Grease lubrication performance prediction is challenging. Only recently that empirical equations to predict grease film thickness for prevailing rolling conditions under fully flooded lubrication taking into account thickener properties and content for low, moderate, and high speeds were developed. At starved lubrication, although new insights abou...

This work uses synchrotron radiation XANES and XPS measurements to investigate the structure of ZDDP tribofilms formed from lubricants contaminated with anhydrous and hydrated ethanol (5%wt). The tribofilms were formed at 40oC from PAO8 lubricant containing only ZDDP additive onto carbon steel specimens using sliding tests, cylinder-on-flat configu...

A significant part of iron ore cost is due to transportation. Around 30% of this cost consists in replacing idlers in conveyor belts. Thus, a proper design of the idler is of great economic importance. Another crucial aspect is the ergonomics related to idlers replacement due to its weight and logistics. Having this in mind, the usage of a robust o...

Conveyor rollers are widely used in the mining industry for ore transportation. However, due to the severe operating conditions, these components may fail prematurely and thus cause high maintenance costs. The failure of these rollers is usually directly related to the service life of their bearings. This service life is greatly influenced by the a...

Resumo: Os materiais poliméricos têm sido comumente utilizados como uma solução atraente para aplicação em componentes mecânicos, em substituição de materiais metálicos, haja visto seu baixo custo e peso. No entanto, esses materiais, diferentemente dos metálicos, estão sujeitos a variáveis que podem comprometer sua aplicação em determinadas condiçõ...

Twin disc tests were employed to assess rail grease formulation effect on friction, wear, and retentivity to propose guidelines for grease selection based on key aspects of grease formulation. Two commercial rail greases plus six in-house formulated greases with the same additive package and consistency, but different thickener types and base oil v...

This paper brings a numerical investigation of non-isothermal grease flow in labyrinth seals. The effects of heat transfer and viscous thermal dissipation in mechanical losses were evaluated. An Arrhenius-type equation was employed to represent the dependence of grease viscosity on temperature and included in the mathematical modeling. The heat tra...

With the trends to increase drain oil interval to reduce the cost of ownership of Heavy-Duty vehicles and to use low ash oils to mitigate degradation of Diesel Particulate Filter performance, the efficiency of lubricant additive s, especially the antiwear ones, are of great interest. However, most of the tribological tests are still done with fresh...

Lipophilic nanoparticles of magnetite (d≈10 nm) functionalized with stearic acid (MagNP) were tested as additive in modern engine oil with low viscosity and high additization. Its thermal and tribological properties were evaluate using TG/DTA and a high frequency reciprocating tribometer, respectively. All tests were performed with the neat oil and...

Purpose The purpose of this paper is to propose a methodology to quantify the error on wear volume evaluation using optical interferometry with image analysis (OI+IA), to establish a lower threshold for wear mapping in practical applications. Design/methodology/approach A three-dimensional surface wear map is quantified by measuring the same area...

A numerical study of the grease friction losses in three different configurations of axial and radial labyrinth seals under different rotational speeds was conducted. The results showed the grease rheology has a significant effect on the viscous torque. On the other hand, the number of labyrinth grooves does not affect substantially the torque for...

Life span of similar idlers designed for the same application varies from months to decades. The main causes of idler premature failures reported in the literature are related to rolling bearing failure due to: contamination, inadequate lubrication and misalignment. In order to understand and postpone / overcome such failures, four types of used id...

Purpose This paper aims to understand the effect of steadite in gray cast iron (GCI) cylinder liners performance (friction and wear) when lubricated with new lube oil formulations to verify if steadite can be reduced or suppressed from cylinder liners composition. Design/methodology/approach The paper presents an experimental approach to quantify...

Highly additized low viscous lubricants, new coatings, and surface treatments have been employed by original equipment manufacturers in several tribosystems to reduce emission and fuel consumption. In this sense, this work investigates the tribological response of four different advanced fully formulated gear oils and three different materials (coa...

Lipophilic magnetite nanoparticles (MagNP; d≈10 nm) functionalized with stearic acid were synthetized and tested as additive in polyalphaolefin synthetic base oil (PAO8) in a model system. The thermal properties of the starting base oil and of the base oil mixed with nanoparticles were evaluated using TG/DTA under inert and oxidizing atmosphere. Th...

Due to the great interest of the automotive industry to quickly and systematically evaluate low wear quantities a new approach based on image processing is presented. By comparing the captured rough surface point cloud using optical interferometry before and after wear, the proposed algorithm was able to estimate the amount of volume wear and mass...

In this work a series of experimental tests were performed with cylindrical thrust roller bearings (TRB) lubricated with grease. The tested greases were formulated with base oils of different grades and/or nature but also different thickener types.t The friction torque was measured under constant load, while varying the rotational speed, at differe...

A pin-on-disc machine was modified to measure traction coefficient and the potential of contact difference under controlled conditions of slide-to-roll ratio, temperature, contact pressure and entrainment speed; oil, grease, grease's base oil and bleed-oil were tested. This new arrangement proved to be efficient to characterise lubricants traction...

Smooth and rough anisotropic surfaces were used to evaluate the influence of surface roughness and texture on the in situ formation of MoS2 from MoDTC in reciprocating sliding tribotests. In order to also assess the influence of the fuel type contamination (gasoline and ethanol) on the oil properties and tribological performance, the experiments we...

Several film thickness measurements were performed with three fresh and aged lubricating greases, their base and bled oils under a wide range of operating conditions using a ball-on-disc test rig with optical interferometry. The analysis of the film thickness measurements is in agreement with the observations of several authors and adds some import...

The influence of the pH in water lubricated sliding contacts was evaluated in terms of friction and wear. The experiments were carried out using a ball-on-disc setup. Si3N4 balls and Al2O3 discs were tested at temperature of (22±2) °C, sliding speed of (1.00±0.03) m/s and normal load of (54.25±0.17) N. Eight types of water with pHs varying from 3 t...

Nowadays, energy saving and environmental awareness are global requirements for creating a sustainable society. Every year billions of rolling bearings are manufactured in the world, of which approximately 90 % are lubricated by grease. There is a consensus in the tribological community, however, that grease lubrication is not as well understood...

Three different lubricating greases and their bleed and base oils were compared in terms of film thickness in a ball-on-disc test rig through optical interferometry. The theoretical values calculated according to Hamrock's equation are in close agreement with the base oil film thickness measurements, which validates the selected experimental method...

Three different lubricating greases and their bleed-oils and base oils were compared in terms of film thickness in a ball-on-disc test rig through optical interferometry. Film thickness measurements of all lubricants, under fully flooded conditions,followed EHL equations and showed that lubricating greases and the corresponding bleed-oils had simil...

The friction torque and the operating temperatures in a thrust ball bearing were measured for seven different types of greases, including three biodegradable greases having low toxicity. These friction torque tests were performed using a modified Four-Ball machine. Rheological evaluations of the lubricating greases were made using a rheometer. Blee...

Thrust ball bearings lubricated with several different types of grease, including three biodegradable low-toxicity greases, were tested in a modified four-ball machine in order to evaluate the bearing friction torque. At the end of each test, grease samples were obtained and analysed through ferrography, allowing the quantification and evaluation o...

Thrust ball bearings lubricated with several different greases were tested on a modified Four-Ball Machine, where the Four-Ball arrangement was replaced by a bearing assembly. The friction torque and operating temperatures in a thrust ball bearing were measured during the tests. At the end of each test a grease sample was analyzed through ferrograp...

The minimization of the power loss and the use of the biodegradable greases have attracting considerable attention. To compare the energetic performance of biodegradable lubricant greases, power loss tests were performed on a modified four-ball machine. A correlation between the grease formulation and rheology was established with its energetic per...

The reduction of the power loss generated in mechanical transmissions and the use of low friction biodegradable lubricants has been attracting considerable attention in recent times. Therefore, it is necessary to develop methods to test and evaluate the performance of such lubricants and compare them with conventional ones. In this sense, a Four-Ba...

2] Instituto Superior de Engenharia do Instituto Politécnico do Porto-ISEP-IPP-ajc@isep.ipp.pt [3] Faculdade de Engenharia da Universidade do Porto-FEUP-jseabra@fe.up.pt Resumo As crescentes preocupações ambientais vêm conduzindo ao desenvolvimento de uma nova geração de massas lubrificantes, com especial atenção para as biodegradáveis e de baixa t...