BEAR engineers have been dedicated to the development and improvement of several life-saving and life-enhancing medical devices.
BEAR engineers have developed a sophisticated biomechanical model of the human musculoskeletal system to assist in studies of hip implant failures. Hip implants are made out of ceramic materials and fail mostly due to fatigue of the materials from cyclic stresses of walking in addition to the brittle nature of ceramic materials. The images on the below show the fracture surface observed with optical microscopy and the overall fracture of the hip implant.
BEAR has inspected and analyzed numerous spinal implant components including screws, rods, and plates. Fractures of rods, backing out of screws, and designs of plates have been investigated; detailed stress analysis of constituents have been performed. Below is an example of a spinal plate implant stress analysis focusing on the screw retention design. The 2D and 3D finite element models have been used for other implants too.
silver bullet—electrosurgical ball electrode
BEAR engineers worked on the development of a new electrosurgical ball electrode, which uses radiofrequency (RF) energy to fuse biological and other materials to tissue surfaces. This device was designed for use in pulmonary surgery to seal air leaks and in solid abdominal organ surgeries to provide a hemostatic tamponade.
Electrosurgical forceps are expensive and easily stick and tear tissue during use. The BEAR team was asked to develop a better design. After several prototypes and extensive testing at BEAR, specialized materials were developed to control heat transfer. Advanced electrical circuits to eliminate micro-sporting were added. The result was a new cauterizing forcep that significantly reduces sticking and tearing tissue during surgery.
Angioplasty balloons are life-saving tools used to insert stents in failing blood vessels. BEAR engineers have worked on this device to quantify their mechanical properties for data that will be used to build better model angioplasty balloons with using a modern computer software. Pictured below is a finite element contour plot used to validate the fact that the stresses in the base material are less than those seen by the balloon. Using this information, BEAR engineers were able to design an apparatus that satisfied the client's needs.
blood vessel connector
BEAR has performed a design review and mechanical analysis for numerous biomechanical devices. One device was a blood vessel connection device. The device was manufactured from an extremely ductile shape memory alloy. The fabrication of this device was a complicated multi-step process and required detailed knowledge of the strains present in the component during each step. BEAR performed a 3D dynamic finite element analysis and closed form solutions to this process.
The metallic components of the implant were exposed to repeated loadings, and a full stress, fatigue, and fracture analysis was performed to demonstrate and determine the expected life of the implant under various loading conditions.