CALCULATED TEMPERATURE RISE AND THERMAL ELONGATION OF STRUCTURAL COMPONENTS, DEPENDING ON ACTION INTEGRAL OF INJECTED LIGHTNING CURRENTS

In the initial phase of an aircraft design, it is valuable to be capable of predicting temperature rise and thermal elongation depending on the actual threat from lightning currents. In this paper equations are stated to calculate the temperature rise of different structures. The analytical expressions established, accounts for the geometry of the structure (round conductor, rectangular cross section, pipe, plane sheet, etc), the material properties (Aluminum, Copper, Carbon Fiber Composites, etc.), the frequency of the current (skin depth) and the Specific Energy (Action Integral). For linear structures (wires, bars etc.), the result is the resistance of the structure, the final temperature, and the thermal elongation depending on geometry and material properties. Regarding arc injection in the centre of plane specimens the equations enables calculation of the temperature as a function of distance from the arc root, and an estimation of the diameter of fatal damages. Finally experiments in the high current lab tend to verify some of the analytical calculations.