Electroforce 3200 series

The femurs were subjected to a three-point bending test. The mechanical properties of the femurs were evaluated at the mid-diaphysis using an electronic universal testing machine (ElectroForce 3200 Series, TA Instruments, USA). The femoral samples were centered and fixed on a three-point bending test stent with two fixed loading points separated by a 20-mm gap. A bending load was applied at a constant displacement rate of 3 mm/min until fractures occurred. The internal and external major and minor axis lengths of the femurs at the fracture points were then measured. The following parameters of the samples were obtained: peak load, fracture load, maximum displacement, and stiffness.

A three-point bending test (ElectroForce 3200 Series, TA Instruments, New Castle, DE, USA) was performed to measure mechanical stress on the femurs. The metrics evaluated included maximum displacement, fracture load, peak load, and stiffness.

In order to compare the elastic-resistance force between the proposed folded and flat magnetic diaphragms, an elastic-resistance force test platform was designed based on the TA ElectroForce system (ElectroForce 3200 series, TA Instruments, BOSE) together with a 22 N load cell (0.2% FS), which could provide the gram-force load’s test, as shown in Supplementary Fig. 15. The displacement data was measured by the integrating displacement sensor (range: ±7.5 mm, 0.03% FS). The flat and proposed folded diaphragms with different shapes were bound in the PLA outer frame through the glue and then installed in the load cell through the PLA basic. A non-magnetic press-head with 2 mm diameter end rounding was installed in the top actuator. The press head forced the center of the diaphragm from 0 to 10 mm with a 1 mm increment, and the force and displacement data were recorded by the TA 3200 ElectroForce controller. Each sample was tested in three cycles. The test results are shown in Fig. 2d.