The Effect of a Hard Coating on the Damping and Fatigue Life of Titanium

Ivancic, Frank T

doi:10.2514/6.2003-1689

Cited by 8 publications

(12 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…nonlinear) damping and stiffness behavior. This dependency has been reported first by Cross et al (1973) about four decades ago and rediscovered by Patsias and co-workers (Shipton and Patsias, 2003;Patsias et al, 2004;Tassini et al, 2006Tassini et al, , 2007 and Palazotto and co-workers (Ivancic, 2003;Ivancic and Palazotto, 2005;Blackwell et al, 2007;Reed, 2007;Reed et al, 2007;Pearson, 2008), where plasma sprayed ceramic coatings on metal substrates were investigated for damping capacity. This nonlinear behavior has resulted in numerous problems with regard to accurately characterizing and modeling these materials.…”

Section: Introductionmentioning

confidence: 90%

Micromechanical theoretical and computational modeling of energy dissipation due to nonlinear vibration of hard ceramic coatings with microstructural recursive faults

Al‐Rub

Palazotto

2010

International Journal of Solids and Structures

View full text Add to dashboard Cite

a b s t r a c tEngine failures due to high-cycle fatigue during severe dynamic vibration have cost the US Air Force an estimated $400 million dollars per year over the past two decades. Therefore, structural materials that exhibit high damping capacities are desirable for mechanical vibration suppression and acoustic noise attenuation. Few experimental studies suggested that hard ceramic coatings, which are commonly used as thermal barrier coatings (TBCs) to protect engine components from high temperatures and corrosion, can also serve as passive dampers due to their unique microstructure which consists of several layers of splats with inter-and intra-microstructural recursive faults (micro-cracks). Therefore, the focus of this study is on the development of a fundamental understanding of the unique microstructural features and mechanisms responsible for this observed energy dissipation in ceramic coatings under nonlinear vibration through the development of a micromechanical computational framework. Inter-and intrafatigue damage and internal friction is simulated through the development of thermodynamic-based nonlinear cohesive laws that consider interfacial degradation, debonding, plastic sliding, and Coulomb/ contact friction between the interfaces of microstructural faults. Representative volume element-based micromechanical simulations are conducted in order to assess the main micromechanical mechanisms responsible for the experimentally observed nonlinear (amplitude-and frequency-dependent) damping in plasma sprayed hard ceramic coatings. It is concluded that the major part of energy dissipation is achieved through contact friction which results from sliding of the splat interfaces along the microstructural recursive faults. Energy dissipation due to progressive decohesion and evolution of new microcracks is not that significant as compared to energy dissipated due to increased friction from existing and new created faults. Therefore, internal friction is the main mechanism that makes TBCs effective dampers.

show abstract

Section: Introductionmentioning

confidence: 90%

Micromechanical theoretical and computational modeling of energy dissipation due to nonlinear vibration of hard ceramic coatings with microstructural recursive faults

Al‐Rub

Palazotto

2010

International Journal of Solids and Structures

View full text Add to dashboard Cite

show abstract

“…The only exception is that a different test specimen is used for vibration-based testing: a 114.3mm square plate with a 3.175mm thickness as opposed to a long cantilever beam. Despite the difficulties in boundary condition control and aerodynamic damping, the vibration-based specimen has been used effectively to extract the damping capabilities of 11 via the bandwidth method. The comparison of the Al 6061-T6 substrate material using the hysteretic energy method and the vibration-based method are shown on Fig.…”

Section: Analysis Of Damping Resultsmentioning

confidence: 99%

A Hysteretic Energy Method for Determining Damping Properties of Hard Coatings

Scott‐Emuakpor¹,

Runyon²,

George³

et al. 2012

53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

3
0
0
0

View full text Add to dashboard Cite

The following manuscript investigates the use of dissipated and stored energies to extract mechanical damping properties from an axially loaded system. This method is observed for three reasons that will benefit the process for determining the damping capacity of hard coatings: 1) it is capable of determining damping properties at larger strain amplitude levels than conventional methods, 2) small strain ranges at stress ratios greater than -1 can be observed to accurately assess damping properties of strain-dependent materials, and 3) the method for extracting damping properties can be automated by using simplified energy calculations. Despite the pros of the hysteretic energy method, there are some limitations that may make its use impractical. One of the major limitations was explored in this study: inconsistency of the hysteretic energy measurement. The hysteretic energy results were observed for several Aluminum 6061-T6 specimens, where a large sample size was averaged to determine if there was consistency in the mean quality factors (a damping parameter) and the relative standard deviations of the sampled energies. Though the results of this study showed consistency in both observed parameters, the resulting values of the quality factors were too low to assess the storage moduli values seen in typical hard coatings, which are in the range of 20-200GPa. The experimental results of this study brings forth the need to address another limiting factor of the hysteretic energy method. In other words, the mitigation of frictional energy losses at the boundary conditions will be explored in future work. NomenclatureD s = system dissipated energy E = elastic storage modulus E b = elastic storage modulus -substrate E c = elastic storage modulus -coating E l = loss modulus h = substrate thickness P a = force amplitude P c = compressive force equation P t = tensile force equation Q = quality factor R = alternating stress/strain ratio R-STD = relative standard deviation t = coating thickness U s = system stored energy  = displacement  a = displacement amplitude  = strain a = strain amplitude  = loss factor 2 Figure 1. Hysteresis loop schematic for energy calculation. c = coating loss factor  s = system loss factor

show abstract

“…Excitation Levels. According to the related literature [30,31], hard coating material not only will affect natural frequency of TCS, but also may lead to the change of modal shape. Therefore, similar to step (6) in Phase I, we firstly use the resulting natural frequencies obtained under different excitation levels in step (2) to excite the coated shell system to reach resonance state, and then we can employ laser rotating scanning method to measure each modal shape of coated TCS under different excitation levels.…”

Section: (4) Measure Each Modal Shape Of Coated Tcs Under Differentmentioning
confidence: 99%

Experimental Study on the Influence on Vibration Characteristics of Thin Cylindrical Shell with Hard Coating under Cantilever Boundary Condition
Li
¹
,
Sun
²
,
Zhu
³

et al. 2017
Shock and Vibration
9
0
9
0
View full text Add to dashboard Cite

This research has experimentally investigated the influence on vibration characteristics of thin cantilever cylindrical shell (TCS) with hard coating under cantilever boundary condition. Firstly, the theoretical model of TCS with hard coating is established to calculate its natural frequencies and modal shapes so as to roughly understand vibration characteristic of TCS when it is coated with hard coating material. Then, by considering its nonlinear stiffness and damping influences, an experiment system is established to accurately measure vibration parameters of the shell, and the corresponding test methods and identification techniques are also proposed. Finally, based on the measured data, the influences on natural frequencies, modal shapes, damping ratios, and vibration responses of TCS with hard coating are analyzed and discussed in detail. It can be found that hard coating can play an important role in vibration reduction of TCS, and for the most modes of TCS, hard coating will result in the decrease of natural frequencies, but the decreased level is not very big, and its damping effects on the higher frequency range of the shell are weak and ineffective. Therefore, in order to make better use of this coating material, we must carefully choose the concerned antivibration frequency range of the shell; otherwise it may lead to some negative effects.

show abstract

The Effect of a Hard Coating on the Damping and Fatigue Life of Titanium

Cited by 8 publications

References 9 publications

Micromechanical theoretical and computational modeling of energy dissipation due to nonlinear vibration of hard ceramic coatings with microstructural recursive faults

Micromechanical theoretical and computational modeling of energy dissipation due to nonlinear vibration of hard ceramic coatings with microstructural recursive faults

A Hysteretic Energy Method for Determining Damping Properties of Hard Coatings

Experimental Study on the Influence on Vibration Characteristics of Thin Cylindrical Shell with Hard Coating under Cantilever Boundary Condition

Contact Info

Product

Resources

About