Displacement vs. place

Regular Marrow bone biopsy needle

Final conceptual design of  ultrasonic biopsy needle

Design, Optimization and Fabrication of an Ultrasonic Surgical Knife

According the good performance of ultrasonic  knife in cutting the soft and hard tissues minimum blooding, and force requirement in this research design, fabrication and electronic driver circuit prototype of an “ultrasonic surgical knife” is studied. To attain the optimal mechanical and electrical design such as long life and more efficiency modeling of the piezoelectric transducer is studied by FEM in Ansys. The FEM model is developed by assumption Axisymmetric with Plane13 element. For obtaining resonant and anti resonant frequency of the transducer in Modal analysis short and open circuit boundary condition are considered respectively then Harmonic analysis method used for obtaining vibration amplitude of the knife blade and structural stresses. First order optimization methods is employed for reducing structural stresses and locate the nodal point of vibration on the knife handle. According to the processes mentioned equivalent circuit of the transducer and power assumption are calculated. Lapping, Wire cut (EDM), photochemical machining and conventional methods of machining are employed in mechanical prototype fabrication. The measured resonant and antiresonant frequency of the ultrasonic knife by Network analyzer compared with the calculated value of the model.

The experimental results show effective performance of the prototyped ultrasonic surgical knife in cutting tissues specially hard tissues such as bone cement.

Click here to see Mode shape of vibration in Ansys FEM.

Click here to see Ultrasonic Surgical Knife practical test.

Design, FEM Modeling and Fabrication of an Ultrasonic Biopsy Needle

Today using of Biopsy needles for sampling of soft tissue in medical is very common. For sampling of hard tissue like as marrow bone primary preparation is needed. In this paper design and application of an Ultrasonic Biopsy Needle for sampling of hard tissue like as bone have been studied. After the definition problem, conceptual design for the system is presented and the designing parts is based on the needs. With the use of FEM analysis in Ansys environment, the design of ultrasonic transducer is done and the first design is optimized for better performance. After the design and simulating of the optimized transducer, the first sample of the design is fabricated and resonant frequency of transducer is measured with Network Analyzer. There are ten present difference between simulation and measured resonant frequency. The use of fabricated set in sampling of hard tissue confirmed the performance of system.

Modeling, Identification, Design and Fabrication of Ultrasonic Transducer Driver Circuit

For all of the applications, ultrasonic transducer is necessary and one of the methods for producing of these waves is use of Electrostrictive property of piezoelectric ceramics. With due attention to the variation behavior of this material relative to driving frequency, obtaining of sufficient electrical model is essential until it can be possible to make drive circuit for ultrasonic transducer and finally it can be able to use in ultrasonic transducers. Network analyzer is used for Identification and the topology of driver circuit is half bridge and for control, it use different phase between voltage and current. The experimental results show the sufficient control of ultrasonic transducer.

Power Ultrasonic Transducer

Click here to see Mode shape of vibration in Ansys FEM.

Displacement vs. place