Fastening assembly

A fastening assembly, comprising:

• a nut, said nut comprising a threaded hole and a nut head, a lower edge of the nut head expanding outwardly to form a skirt portion, and a bottom surface of the skirt portion being provided with a plurality of consecutive ramps, where adjacent consecutive ramps form a bulkhead in between, a bottom of the threaded hole extending downwardly to form a blocking ring, and an outer edge of the blocking ring forming a barrier surface toward a surface of the consecutive ramps;
• a washer, said washer being an annular body, where its outer diameter is less than or equal to an outer diameter of the skirt portion, said washer having a through hole at its center, a part of the through hole expanding to form a diameter-enlarged hole, the through hole and the diameter-enlarged hole forming a shoulder at their junction, a top surface of said washer being provided with a plurality of consecutive ramps, the number of the consecutive ramps being the same with that of the consecutive ramps of said nut, adjacent consecutive ramps forming a bulkhead in between, an outer circumferential surface of said washer being provided with at least one notch, wherein
• the barrier surface of said nut confines the shoulder of said washer that said washer is not allowed to separate from said nut, the maximum vertical distance from the barrier surface to the shoulder being greater than the vertical height of the bulkhead.