In the present study, for the first time, the shapes of slots of wide blade horns are optimized using Non-Uniform Rational B-Spline (NURBS) curves. Here, two 20 kHz horns with different gain ratios (2.5 and 3.5) are designed. The amplitude uniformity and maximum stress of horns are regarded to design. Some control points are used to define the shape of slots, and the position and weight of these points are determined. The genetic algorithm with a link to Abaqus is applied for the optimization process. The simulation results show that the designed horns have high amplitude uniformity equal to 0.978, 0.965. Also, the maximum stresses are 73.08 MPa and 78.52 MPa, which are less than the fatigue strength with a safety factor of 2. It is found that the stress values in the bottom of NURBS-shaped slots are considerably lower than the simple slots, making it possible to design the horns with a higher gain ratio without fatigue failure. Finally, the performance of the present design is verified by doing some experiments on the fabricated horn, which confirms that the proposed design can be successfully utilized as a new method to design wide blade horns.
