Modelling of mechanical failure due to constrained thermal expansion at the lightning arc attachment point in carbon fibre epoxy composite material

Coupled Thermal-Mechanical Progressive Damage Model with Strain and Heating Rate Effects for Lightning Strike Damage Assessment

“…[1,[3][4][5][6][7]. Research is on-going to model the plasma developed during a strike using Finite element or CFD simulations and the resulting loading to the specimen [8,9,[18][19][20][21][10][11][12][13][14][15][16][17]. The majority of simulation authors have modelled specimen behaviour only and assumed a surface load, employing FE models to characterise the thermal damage [8,10,11,14,16,20] or damage as a result of pressure loading [11][12][13].…”

“…The majority of simulation authors have modelled specimen behaviour only and assumed a surface load, employing FE models to characterise the thermal damage [8,10,11,14,16,20] or damage as a result of pressure loading [11][12][13]. More recent works have incorporated thermal expansion effects [15,17]. However, a modelling approach using all three of these loads has not been developed and the vast majority of models with individual loads have assumed / idealised surface loads which do not represent the complexities of the lightning plasma.…”

“…While the results of both works were closer to experimental results than thermal damage alone, both have neglected one of the three key physics involved, either pressure or thermal expansion. Constrained thermal expansion was also considered by Foster et al using the outputs of a preceding thermal-electric simulation to generate the temperature profile during the simulated strike [15]. Karch et al [12] conducted an extensive study for Waveform D (96.4kA, 20 MPa peak) pressure loading using a progressive damage model with four bilinear softening laws.…”

“…Foster et al [15] indicated that, to best knowledge, no single material data set was available within literature which incorporated the combined heating rates, high temperatures and high strain-rates expected in a composite material during a lightning strike event. Foster incorporated these effects individually to analyse their influence.…”

“…Foster incorporated these effects individually to analyse their influence. Surface damage area varied by 30 and 50% respectively for heating rate and strain rate dependent material properties [15]. More generally, studies have been conducted to experimentally determine the influence of strain on composite material properties [32,[34][35][36][37][38][39][40] however significantly less have focused on the combined effects of strain and heating rates [41,42].…”