Lightning stroke dynamic damage simulation method for composite material

The invention discloses a lightning stroke dynamic damage simulation method for a composite material, and the method specifically comprises the steps: 1, building a three-dimensional geometric model of the composite material, carrying out the grid division of the geometric model, defining the grid type, and defining the electrothermal physical attributes and field boundary conditions; step 2, applying a lightning stroke current component and a heat flow load to the geometric model, then calculating a pyrolysis degree field, a potential field and a temperature field of each grid unit under each time step, and if the pyrolysis degree of the corresponding grid unit under the current time step is less than or equal to 0.4, not updating the grid unit; if the pyrolysis degree is larger than 0.4, the grid unit is updated, the pyrolysis degree field, the potential field and the temperature field of the grid under the current time step and the dynamic damage of the lightning stroke attachment area on the surface of th