Boundary value problems for a circular-arc crack embedded in an infini
te medium due to a point heat source are formulated and solved in clos
ed form. Based on the Hilbert problem formulation and a special techni
que of contour integration, exact solutions of a semicircular crack ar
e obtained in an explicit form. It is found that the thermal stresses
or temperature gradient near the tips of a curved crack always possess
the characteristic inverse square-root singularity in terms of the ra
dial distance away from the crack tip under the application of a heat
source. The simultaneous existence of mode-I and mode-II stress intens
ity factors are shown in this article to be dependent on the strength
of a heat source, heat conductivity, as well as thermal and elastic is
otropy. The nonnegative mode-I stress intensity factor is found to be
present in this article for the application of the heat sink, which va
lidates the fully open crack assumption.