Hongwei Wang (2024) “Study on Simplified Calculation of Ultrasonic Method for Detecting Void in Concrete Filled Steel Tube Based on Sound Velocity”, The International Journal of Multiphysics, 18(2), pp. 175 - 181. Available at: https://www.themultiphysicsjournal.com/index.php/ijm/article/view/1252 (Accessed: 16October2025).