医疗器械扭转试验

In addition to axial and multi-modal loading in vivo, medical devices often experience 扭转 and bending during use. For some orthopedic devices such as bone screws, the 扭转al loading is imposed during the implantation, and the device needs to resist failure during the applied 扭转. 在一些固定装置中, the head is designed to shear off at a predetermined torque so that it does not remain within the implantation site. For intravascular applications, the device often experiences 扭转al loading post implantation.

例如, stent-grafts used in peripheral indications can experience 扭转 due to normal limb motion. Devices intended for aortic repair can sometimes experience 扭转al loading due to twisting of the torso. Over the years im体育APP has performed hundreds of 扭转al testing applications and has developed a toolbox of test fixtures and techniques for these applications.

im体育APP has many test systems that were designed to perform 扭转al testing. 我们的大部分BOSE/TA elf3300, Instron ElectroPuls e3000, and MTS systems are equipped with 扭转 stages to provide rotational motion to single or multiple specimens. This rotational motion can be used independently or in concert with the axial systems for multi-modal fatigue.

Specifications for 扭转al tests typically include the rate of rotation (deg/s), 旋转频率(Hz), 峰值扭矩(N*m), 或峰值旋转(度). 此测试可用于疲劳测试, 验证和功能测试, 破坏性的测试, 以及材料表征. Results typically take the form of cycles at fractures, 断裂处最大旋转, 断裂时最大扭矩, 或者一个简单的扭矩vs. 角位移曲线.

We can develop and implement 扭转 testing fixtures for a variety of devices, including:

• Medical bone screw insertion/removal and fracture torque characterization
• 椎间盘植入物疲劳试验
• Torsional modulus characterization of fine l wire
• Combined cantilevered and pure bend testing of peripheral stents
• Cantilevered and pure bending of instrument cables
• 牙签旋转断裂试验
• 手术工具的验证
• SFA步态测试(拉力/弯曲/扭转)

骨螺钉测试

ASTM F543-13 is a test method used to measure the 扭转al yield strength, maximum torque and breaking angle of bone screws under standard conditions. im体育APP carried out ASTM F543-13 and ISO 6475:1989 compliant Fiducial Bone Screw insertion and removal torque testing using the rotational stage of a BOSE/TA ELF3300AT.

A pair of linear bearings with an adjustable weight cylinder were used to apply smooth, 对样品施加恒定轴向压力, while the rotation stage provided the requisite angular displacement (driving torque) to embed the screw in a block of simulated bone material. Data was collected in the form of angle of rotation vs. 转矩和轴向载荷.

im体育APP also performed the accompanying ultimate 扭转al strength testing, holding the screw stationary and applying a measured angular displacement to the driving head until fracture occurred.

手术工具测试

im体育APP has tested a wide variety of surgical tools and accessories in addition to the actual implants. Surgical tools need to be able to withstand rotational forces during use and are often tested to simulated forces they will experience during routine use in the operating room to observe any fracture, 测试过程中拆卸或损坏.

The torque-to-fracture testing described was performed on an Instron ElectroPuls E3000 tester with a modular 扭转 stage and torque cell. Data was provided in the form of a continuous torque vs. 角度图和最大扭矩值. MDT also performed the accompanying axial force, 多方向三点弯曲, 以及本系列设备的缝合拉伸试验. Tests were performed on the entire device as well as on device components.

外周支架测试

Combined Cantilevered/Bend 测试 (Wag Bend) testing is carried out using the rotational stage of a BOSE/TA ELF3300AT. Constant physiological temperature and pressure in the samples are maintained by the recirculation of saline through a heated mean-pressure tank and the stationary manifold that provides the “base” for the bend. Bending radius and motion are verified through use of an overhead high-speed video camera and dimensional analysis software. 各种各样的样品直径, 长度, and bending angles/radii can be accommodated in runs of up to n=12 samples.

国家林业局测试

im体育APP has carried out many SFA gait motion tests on a variety of peripheral devices in compliance with ASTM 2942-13. The SFA tester mounted on a BOSE/TA ELF3300AT uses both the axial and rotational actuators to apply cyclical tension, 扭转, and local bending to the samples over test runs of many millions of cycles. Physiological pressure and temperature in the samples are maintained by a mean-pressure heated saline recirculation system.

结论

总之, the importance of 扭转 testing for many different types of medical devices is paramount. im体育APP's 扭转 test instruments coupled with several decades of 扭转 testing expertise have resulted in the design of a variety of 扭转 fixtures and test protocols for many challenging applications.

立即im体育APP to discuss how 扭转 testing may complement your medical device mechanical testing and regulatory submission data.