The inorganic analogous of graphene has demonstrated many potential applications in novel devices. Thus, understanding the mechanical properties of hexagonal boron-nitride sheets is of great importance. To this end, the molecular dynamics (MD) simulations are employed to impose tensile load on the sheets in order to compute their mechanical properties and fracture propagation. Moreover, since the presence of defects is undeniable, the effects of two important kinds of defects, i.e. vacancy and Stone-Wales, on Young's modulus, ultimate strength, failure strain and fracture patterns corresponding to different chiralities are explored. It is observed that Young's modulus reduces linearly with increasing the defect percentage, whereas the ultimate strength and failure strain vary with defect percentage in a homographic-like trend with specific asymptote for each case. According to the results, the presence of vacancy defects reduces the aforementioned values more considerably compared to Stone-Wales defects, especially in the case of zigzag direction. Finally, it is found out that in the defective sheets, fracture begins at the location of sheet with higher densities of defect and propagates through the defect sites.
