A B S T R A C T A novel fretting fatigue experimental methodology is presented for mimicking the salient fretting variables for arbitrary axial locations within a complex spline coupling geometry, under combined torque, axial loading and rotating bending moment. The approach permits the simulation, in a simplified test arrangement, of the superimposed multiaxial fretting conditions between the spline teeth. This is achieved via the combination of a low frequency in-plane cyclic normal clamping load and a higher frequency out-of-plane cyclic fatigue stress. The latter is known from spline fatigue tests to play a critical role, along with torque and axial loads, in fretting fatigue cracking of splines.
N O M E N C L A T U R Eα = correction factor for axial variation in contact pressure along representative specimen model a 1 = spline axial direction contact width a 2 = spline tooth contact width in flank direction β p = helix angle at pitch circle diameter (PCD) B = total bending moment b 1 = width of fretting bridge foot contact with fatigue specimen B n = non-dimensionalized bending moment B m yp = bending moment capacity of the nominal externally splined shaft b = fatigue strength exponent c = fatigue ductility exponent D fret = fretting fatigue damage factor for modified Smith-Watson-Topper (SWT) approach δ = relative slip amplitude between two contacting surfaces E = Young's modulus ε f = fatigue ductility coefficient F i = in-plane applied force in simplified test F o = out-of-plane applied force in simplified test F sp = total force along tooth flank contact width F nom o = nominal spline contact force per unit width F n = non-dimensionalized axial force F m yp = axial load capacity of the nominal externally splined shaft μ = coefficient-of-friction (COF) N f = the number of cycles to failure N = number of teeth in the spline coupling Correspondence: S. B. Leen.
SummaryAn analytical solution is given for the one-dimensional distribution of temperature in a web of an idealised multi-cell wing structure when the adiabatic wall temperature variation is assumed to be either an instantaneous or a linear function of time. The maximum temperature difference between skin and web centre is computed for a range of structural geometries and thermal parameters. Thermal stresses are calculated assuming a parabolic temperature distribution in the web.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.