Apparatus and method for in situ testing of microscale and nanoscale samples
View Patent ↗According to example embodiments of the invention, a microscale testing stage comprises a frame having first and second opposing ends and first and second side beams, at least one deformable force sensor beam, a first longitudinal beam having a free end, a second longitudinal beam having a facing free end, a support structure, and a pair of slots disposed at each of the free ends. In certain embodiments, a separately fabricated microscale or nanoscale specimen comprises a central gauge length portion of a material to be tested, and first and second hinges providing a self-aligning mechanism for uniaxial loading. In other embodiments, a layer of a conductive material defines first and second conductive paths and an open circuit that can be closed by the specimen across the gap. In other embodiments, the stage is formed of a high melting temperature material.
1. A microscale testing stage comprising:
a frame having first and second opposing ends and first and second side beams;
at least one deformable force sensor beam near the first end extending laterally across said frame between the first and second side beams;
a first longitudinal beam bisecting said at least one force sensor beam and having a free end;
a second longitudinal beam having a free end facing the free end of said first longitudinal beam to define a gap therebetween;
a support structure disposed near the second end;
a pair of slots disposed at each of the free ends of the first and second longitudinal beams, respectively; and
a separately fabricated microscale or nanoscale specimen, said specimen comprising:
a central gauge length portion of a material to be tested;
first hinges disposed at each of opposing longitudinal sides of said gauge length portion;
second hinges disposed at each of opposing longitudinal sides of said first hinges, wherein said first hinges are disposed between said second hinges and said gauge length portion, said first hinges and said second hinges providing a self-aligning mechanism for uniaxial loading; and
opposing ends for inserting into each of the pair of slots, respectively.
2. The testing stage of claim 1 , wherein each of said first hinges and said second hinges are configured to have a high bending stiffness along a predetermined direction and a lower bending stiffness along other directions.
3. The testing stage of claim 2 , wherein the predetermined direction for said first hinges is substantially perpendicular to said predetermined direction for said second hinges.
4. The testing stage of claim 1 , wherein cross-sectional areas of each of said first hinges and said second hinges are larger than a cross-sectional area of said gauge length portion.
5. The testing stage of claim 4 , wherein a bending stiffness of each of said first hinges and said second hinges is much smaller than a bending stiffness of said gauge length portion along a predetermined direction.
6. The testing stage of claim 1 , wherein each of said pair of slots has a depth within said frame that is about half a thickness of said stage.
7. The testing stage of claim 1 , wherein said specimen further comprises:
a pair of opposed measurement arms supported by said specimen, each of said pair of opposed measurement arms including a portion extending parallel to a length of said specimen and providing a measurement gauge.
8. The testing stage of claim 1 , wherein said support structure comprises a plurality of laterally extending beams between said first and second side beams, said second longitudinal beam bisecting said laterally extending beams.