Duhamel's principle, in partial differential equations it gives the solution to the nonhomogenous wave equation (named for Jean-Maria-Constant Duhamel)
Duhamel's integral is used in engineering / response theory to calculate the response of a linear system to an arbitrary excitation, provided the excitation to an impulse function is known
Duhamel's formula – solution to general inhomogeneous linear equations
19617 Duhamel, an asteroid named fro Jean-Maria-Constant Duhamel