YY_T0119.5-2014 Spinal Implant Internal Fixation System Components:

Part 5: Test method for determination of static and fatigue bending strength of metal spinal screws

This section of YY/T 0119 specifies the test methods for determining the static and dynamic bending performance of metal spinal screws. This section is applicable to metal spinal screws used in spinal fixation implants.

This section aims to provide a method for mechanical characterization of spinal screws with different component types. At present, there is not enough knowledge to predict the specific results of screw design, so the purpose of this experimental method is not to define the performance level of spinal screws.

Testing equipment:

PBSC-BP30 bone screw performance testerPBFT-BP30 Plate Bending Fatigue Testing Machine

Overview of Experimental Methods:

Apply quasi-static cantilever bending load to the spinal screw to record the mechanical response of the component corresponding to the applied load. By analyzing the load deflection curve, determine the data used to derive the bending performance of spinal screws.

2. Apply a sinusoidal suspension bending load of a predetermined frequency to a given spinal screw sample. The fatigue test continues until one of the following three situations: sample failure, reaching the limit of termination test, or reaching the predetermined number of cycles (termination limit). The experimental result information is used to draw a bending moment cycle curve to characterize the general fatigue characteristics of a given spinal screw type within the range of applied bending torches. In addition, under appropriate circumstances, this result information can be used to determine the median fatigue bending moment of spinal screws at a specified number of cycles N.

Test system requirements; Static bending test

Axial loading equipment: a testing machine capable of providing tensile or compressive loads at a constant displacement rate.

Force sensor: a sensor that meets the requirements of GB/T 16825.1, has been calibrated, and can measure axial loads. Its output results can be read by suitable recording equipment.

Displacement sensor: a sensor that has been calibrated and can measure axial displacement with an accuracy of not less than ± 1% of its range. Its output results can be read by suitable recording equipment.

PBSC-BP30 bone screw performance tester equipment parameters:

Force measurement range 20kg

Pull out force measurement range ≤ 200kg

Torque measurement range 0-3Nm

Measurement accuracy of 0.5 level, screw in and screw out load ≤ 11.17N, self tapping axial compression load 2N/s (constant speed increasing, accuracy: ± 1N/s)

Test stroke ≤ 300mm

Resolution 0.01N/0.001Nm

Test mode driving torque, self attack performance, torsional performance, pull-out, insertion force test

Testing speed 0.5-200mm/min

Continuously variable transmission; 0.5~30r/min

Dimensions 470 (L) X440 (B) X1000 (H) mm

Power supply AC220V ± 22V, 50Hz

Weight approximately 60kg

PBFT-BP30 Plate Bending Fatigue Testing MachineEquipment parameters:

Maximum dynamic test force 3000N

The dynamic indication accuracy is within the range of 5% -100%, with an indication accuracy of ± 0.5% Amplitude fluctuation ± 0.5% FS

Actuator stroke 100mm

Frequency range 0.1-15Hz 6. Controller type: displacement, force, closed-loop control

Main experimental waveforms include sine wave, triangular wave, rectangular wave, and oblique wave

The center height of the pin hole is 1000mm, and the center height of the upper and lower pin holes is 1000mm

The servo motor of the crossbeam lifting mechanism drives the crossbeam lifting through a synchronous belt; Equipped with a manual controller, the lifting is controlled by manually shaking the wheel;

High strength bolt locking mechanism for crossbeam locking, with a tightening torque of 150NM

The clear distance between two columns is 505mm

The durability test cycle is infinite

Equipment power 3500W

Power supply voltage~380V ± 10%; 50Hz (must be reliably grounded)~220V ± 10%; 50Hz (must be reliably grounded)

Rack size (LWH) 700x685x2086mm

Machine weight ≈ 500kg

No fixtures available (customized according to sample size or provided by the user)