Influence of Coating Thickness and Substrate Elasticity on the Tribological Performance of PEEK Coatings

2012 ◽  
Author(s):  
Yuanyuan Wang ◽  
Elon J. Terrell
Keyword(s):  
Energy Dissipation ◽  
Coating Thickness ◽  
Crack Nucleation ◽  
Normal Load ◽  
Experimental Tests ◽  
Element Model ◽  
Substrate Material ◽  
Lubricating Capacity ◽  
Substrate Elasticity ◽  
Peek Coating

When a material is subjected to repeated sliding contact, a surface fatigue and crack nucleation may occur on its surface. This damage weakens the material and can lead to debris formation. In many practical engineering assemblies, a thin PEEK (poly-ether-ether-ketone) coating is applied to reduce the damage, since PEEK exhibits wear resistance, corrosion resistance self-lubricating capacity and is lightweight. However, little is known about the effect of coating thickness on the plastic deformation, residual stresses and energy dissipation of PEEK when placed under sliding load. Moreover, the effect of substrate rigidity on coating stresses and deformation under sliding load are also under-researched. Having such knowledge is of significant importance in order to reduce damage of engineering parts and extend their lifetime. In this study, the effects of PEEK coating thickness and substrate elasticity were analyzed using a 3D ball-on-flat finite element model as well as experimental analysis using a linear reciprocating tribometer. The experimental tests were performed with samples that incorporated PEEK coatings of various thicknesses on alumina and steel substrates. It was found that under a constant normal load, stresses, strain and energy dissipation were sensitive to both substrate material and coating thickness. It is shown from both simulation and experiment, the optimum combination, within the range the experiments were conducted, for minimizing residual stress and possible fatigue damage was an alumina substrate with 35μm PEEK coating thickness.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

scholarly journals Material parametrization of natural rubber based compound and characterization of crack propagation under consideration of dissipative effects

2021 ◽  
Author(s):  
Dan Pornhagen ◽  
Konrad Schneider ◽  
Markus Stommel
Keyword(s):  
Energy Dissipation ◽  
Crack Propagation ◽  
Natural Rubber ◽  
Experimental Tests ◽  
Material Behavior ◽  
Prony Series ◽  
Material Forces ◽  
Cracking Behavior ◽  
Dissipative Effects

AbstractMost concepts to characterize crack propagation were developed for elastic materials. When applying these methods to elastomers, the question is how the inherent energy dissipation of the material affects the cracking behavior. This contribution presents a numerical analysis of crack growth in natural rubber taking energy dissipation due to the visco-elastic material behavior into account. For this purpose, experimental tests were first carried out under different load conditions to parameterize a Prony series as well as a Bergström–Boyce model with the results. The parameterized Prony series was then used to perform numerical investigations with respect to the cracking behavior. Using the FE-software system ANSYS and the concept of material forces, the influence and proportion of the dissipative components were discussed.

scholarly journals Effect of Bottom Geometry on the Natural Sloshing Motion of Water Inside Tanks: An Experimental Analysis

2021 ◽  
Vol 11 (2) ◽  
pp. 605
Author(s):  
Antonio Agresta ◽  
Nicola Cavalagli ◽  
Chiara Biscarini ◽  
Filippo Ubertini
Keyword(s):  
Energy Dissipation ◽  
Water Depth ◽  
Shear Force ◽  
Experimental Tests ◽  
Shear Load ◽  
Damping Properties ◽  
Base Shear ◽  
Structure Interaction ◽  
Sloshing Phenomenon ◽  
Key Aspects

The present work aims at understanding and modelling some key aspects of the sloshing phenomenon, related to the motion of water inside a container and its effects on the substructure. In particular, the attention is focused on the effects of bottom shapes (flat, sloped and circular) and water depth ratio on the natural sloshing frequencies and damping properties of the inner fluid. To this aim, a series of experimental tests has been carried out on tanks characterised by different bottom shapes installed over a sliding table equipped with a shear load cell for the measurement of the dynamic base shear force. The results are useful for optimising the geometric characteristics of the tank and the fluid mass in order to obtain enhanced energy dissipation performances by exploiting fluid–structure interaction effects.

scholarly journals Interlocking birch plywood structures

2021 ◽  
pp. 095605992110222
Author(s):  
Chrysl A Aranha ◽  
Markus Hudert ◽  
Gerhard Fink
Keyword(s):  
High Surface ◽  
Surface Hardness ◽  
Experimental Tests ◽  
Digital Fabrication ◽  
Element Model ◽  
Component Level ◽  
Geometrical Properties ◽  
Stiffness Properties ◽  
The Face ◽  
Strength And Stiffness

Interlocking Particle Structures (IPS) are geometrically stable assemblies, usually fabricated from plate type elements that are interconnected by slotted joints. IPS are demountable and their components have the potential to be used and reused in different structures and configurations. This paper explores the applicability of birch plywood panels, which are characterized by a high surface hardness, for this type of structural system. Experimental tests were conducted to determine the mechanical properties of birch plywood plates. Moreover, IPS connections with different geometrical properties were investigated for two different load exposures: bending and rotation. The characteristics under bending exposure are influenced by the orientation of the face-veneers. For the rotational load exposure, very small strength and stiffness properties have been identified. A linear elastic finite element model is presented that shows a wide agreement with the test results. The study serves as an initial probe into the performance of IPS structures at the component level. Various aspects that are relevant for the design of IPS, such as the assembly, the accuracy and challenges regarding digital fabrication, the durability, and the structural performance are discussed.

scholarly journals Experimental and Numerical Investigation on the Perforation Resistance of Double-Layered Metal Shield under High-Velocity Impact of Armor-Piercing Projectiles

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 626
Author(s):  
Riccardo Scazzosi ◽  
Marco Giglio ◽  
Andrea Manes
Keyword(s):  
High Strength Steel ◽  
Steel Plate ◽  
Experimental Studies ◽  
Practical Interest ◽  
High Strength ◽  
Experimental Tests ◽  
Element Model ◽  
Transportation Systems ◽  
Metal Shield ◽  
Softening Parameter

In the case of protection of transportation systems, the optimization of the shield is of practical interest to reduce the weight of such components and thus increase the payload or reduce the fuel consumption. As far as metal shields are concerned, some investigations based on numerical simulations showed that a multi-layered configuration made of layers of different metals could be a promising solution to reduce the weight of the shield. However, only a few experimental studies on this subject are available. The aim of this study is therefore to discuss whether or not a monolithic shield can be substituted by a double-layered configuration manufactured from two different metals and if such a configuration can guarantee the same perforation resistance at a lower weight. In order to answer this question, the performance of a ballistic shield constituted of a layer of high-strength steel and a layer of an aluminum alloy impacted by an armor piercing projectile was investigated in experimental tests. Furthermore, an axisymmetric finite element model was developed. The effect of the strain rate hardening parameter C and the thermal softening parameter m of the Johnson–Cook constitutive model was investigated. The numerical model was used to understand the perforation process and the energy dissipation mechanism inside the target. It was found that if the high-strength steel plate is used as a front layer, the specific ballistic energy increases by 54% with respect to the monolithic high-strength steel plate. On the other hand, the specific ballistic energy decreases if the aluminum plate is used as the front layer.

Identification of Process Damping Coefficient Based on Material Constitutive Property

2014 ◽  
Author(s):  
Xiaoliang Jin
Keyword(s):  
Energy Dissipation ◽  
Flank Wear ◽  
Orthogonal Cutting ◽  
Element Model ◽  
Machining Process ◽  
Damping Coefficient ◽  
Chatter Stability ◽  
Workpiece Material ◽  
Process Damping ◽  
Constitutive Property

The contact between the tool flank wear land and wavy surface of workpiece causes energy dissipation which influences the tool vibration and chatter stability during a dynamic machining process. The process damping coefficient is affected by cutting conditions and constitutive property of workpiece material. This paper presents a finite element model of dynamic orthogonal cutting process with tool round edge and flank wear land. The process damping coefficient is identified based on the energy dissipation principle. The simulated results are experimentally validated.

On the Performance of Wavy Dry Friction and Piezoelectric Hybrid Flexible Dampers

2021 ◽  
Author(s):  
Yaguang Wu ◽  
Yu Fan ◽  
Lin Li ◽  
Zhimei Zhao
Keyword(s):  
Piezoelectric Material ◽  
Dry Friction ◽  
Normal Load ◽  
Harmonic Balance Method ◽  
Element Model ◽  
Total Output ◽  
Friction Damper ◽  
Damping Effect ◽  
Thin Walled Structures ◽  
Friction Plate

Abstract This paper proposes a flexible dry friction plate to mitigate the vibration of thin-walled structures for one resonance crossing. Based on a cantilever beam-friction damper finite element model, the geometry and material parameters of the friction plate are optimized numerically through steady-state response analyses by the widely-used Multi-Harmonic Balance Method (MHBM). In order to further improve the damping effect, piezoelectric material is distributed to the flexible damper, and two types of dry friction and piezoelectric hybrid dampers are explored, namely semi-active and passive, respectively. For semi-active hybrid dampers, piezoelectric material is used as an actuator to adjust the normal load applied to the friction interface in real time, so that the friction damping is improved. For passive ones, piezoelectric material is used as a transducer, which dissipates the strain energy stored in the wavy plate by the shunting circuit, additional shunted piezoelectric damping contributes to the total output damping accordingly. Better damping effect compared with the friction baseline is realized for the two types ideally. This damping module has a simple structure and avoids the problem of installation and maintenance of piezoelectric material which is generally bonded to the host structure. Technical challenges are: the semi-active type requires excessive voltage applied to the piezoelectric actuator, while the passive one needs to connect a programmable synthetic circuit.

Thermal Effects in Contact Fatigue Under Oscillatory Normal Load

1965 ◽  
Vol 87 (1) ◽  
pp. 177-184 ◽  
Author(s):  
R. A. Burton ◽  
J. C. Tyler ◽  
P. M. Ku
Keyword(s):  
Energy Dissipation ◽  
Dynamic Load ◽  
Normal Load ◽  
Fatigue Cracks ◽  
Thermal Transformation ◽  
Contact Fatigue ◽  
Contact Temperature ◽  
Flat Specimen ◽  
Exponential Relationship ◽  
Specimen Temperature

Experiments are reported wherein contact fatigue was brought about by the application of an oscillatory normal load between a ball and a flat specimen. Plots of the flat-specimen temperature versus time showed that a rapid temperature rise occurred in the initial stage of crack formation, and thus provided an early indication of fatigue. Thermal resistances were measured for the apparatus components as well as the specimen contact. Using these, it was possible to apply the measured flat-specimen temperature to obtain estimates of the contact temperature as well as the energy dissipation rate prior to the incidence of fatigue cracks. It was shown that the contact temperature did not rise sufficiently to produce annealing in the test specimens. Thus, toroidal rings of hardened and softened material in the stressed zone could not be attributed to thermal transformation of the bearing steel. It was also shown that energy dissipation due to cyclic loading varied in approximate exponential relationship with dynamic load, and decreased upon increase of static load when dynamic load was maintained constant.

scholarly journals Mechanical Behavior of a Calcium Phosphate Ceramic Bone Graft Used in the Rehabilitation of a C4 Human Vertebra

2007 ◽  
Vol 7-8 ◽  
pp. 101-106 ◽  
Author(s):  
Juan Alfonso Beltrán-Fernández ◽  
Luis Héctor Hernández-Gómez ◽  
R.G. Rodríguez-Cañizo ◽  
G. Urriolagoitia-Calderón ◽  
G. Urriolagoitia-Sosa ◽  
...  
Keyword(s):  
Bone Graft ◽  
Experimental Tests ◽  
Element Model ◽  
Calcium Phosphate Ceramic ◽  
Compression Load ◽  
Head Weight ◽  
Anterior Side ◽  
Average Patient ◽  
On Line ◽  
Cervical Plate

The main results of a static analysis with a finite element model of the cervical section between C3 – C5 of a human spine are reported. In this case, it is assumed that the element C4 is completely damaged and has to be replaced. Therefore, a bone graft was installed between the anterior side of C3 and C5. Besides, a cervical plate of 55 mm. was fixed at the same side with 4 expansive screws. The resultant stresses caused by compression loads were analyzed and the displacements between the graft and adjacent vertebrae were calculated. Three loading conditions were applied: 80 N, 637.5 N and 6374.5 N. The first one corresponds to the head weight. In the second case, it is assumed that the average patient weight is supported by those vertebrae, while in the last one; the compression load failure is applied on the vertebrae. Results show that displacements were lower than 3 mm between the graft and the adjacent vertebrae. In accordance with the concept of spine stability after Müller [1], the arrangement is a stable one. Another advantage is that no wires are used in this surgical technique. Two more issues should be noticed. There is no risk that the plate may be broken and the geometry of the bone graft allows bone regeneration. These results are on line with those observed in preliminary experimental tests with porcine vertebrae.

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