Fig. 1 Contactless 3D printing via material extrusion on an acoustic air bed. Concept schematic of directing a tailored acoustic wavefront to contactlessly support material during extrusion. Engineered arrangement of transducers induces an acoustic radiative force ( F → a r f ... More about this image found in Contactless 3D printing via material extrusion on an acoustic air bed. Conc...

Fig. 2 Numerical finite element acoustic model and analysis of the acoustic radiation force. ( a ) Model of the source array as used experimentally (see Supplemental Material on the ASME Digital Collection Videos 1 and 2). ( b ) Cross section of the transducer array and the resulting acoustic fi... More about this image found in Numerical finite element acoustic model and analysis of the acoustic radiat...

Fig. 3 Analysis of acoustic force components that support the filament: ( a ) Vertical radiation force ( F y ) exerted on the circular filament cross section. ( b ) Horizontal force ( F x ) exerted on the filament. The filament is extruded along the Z -axis; gravity points in the − Y direc... More about this image found in Analysis of acoustic force components that support the filament: ( a ) Vert...

Fig. 4 Analysis of optimal transducer array arrangement during extrusion. Vertical acoustic radiation force ( F y ) as a function of position on the plane comprising the extrusion direction ( Z ) and the gravity direction (− Y ). ( a ) Transducer spacing is 1 mm; ( b ) transducer spacing is 3 m... More about this image found in Analysis of optimal transducer array arrangement during extrusion. Vertical...

Fig. 5 Analysis of contactless material support in three dimensions. Horizontal (lateral) acoustic radiation force ( F x ) as a function of horizontal position ( x -axis) where x = 0 is the stable equilibrium position. Filament diameter is 0.4 mm, and the total length is 40 mm. Extruded filam... More about this image found in Analysis of contactless material support in three dimensions. Horizontal (l...

Fig. 6 Experimental dynamics of extrusion of a 3D-printer filament. ( a ) Acoustic field is turned OFF, and the filament sags under its weight as it is extruded. See also Supplemental Material Video 1; ( b ) acoustic field is turned ON; the filament is supported by an air bed and better maintain... More about this image found in Experimental dynamics of extrusion of a 3D-printer filament. ( a ) Acoustic...

Fig. 1 Fundamental principle of BTT system More about this image found in Fundamental principle of BTT system

Fig. 2 Overview of the proposed methodology More about this image found in Overview of the proposed methodology

Fig. 3 Calculation of stagger angle More about this image found in Calculation of stagger angle

Fig. 4 FE model of the blade with tip section details More about this image found in FE model of the blade with tip section details

Fig. 5 Typical mode shapes and natural frequencies of the rotor blade: ( a ) 1B (302 Hz), ( b ) 1T (1014 Hz), ( c ) 2B (1472 Hz), ( d ) 2T (2263 Hz), and ( e ) 1C (2729 Hz) More about this image found in Typical mode shapes and natural frequencies of the rotor blade: ( a ) 1B (3...

Fig. 6 Axial sensor locations for BTT systems More about this image found in Axial sensor locations for BTT systems

Fig. 7 Calibration factors predicted by traditional method More about this image found in Calibration factors predicted by traditional method

Fig. 8 Modal displacement of different axial locations: ( a ) 1B mode, ( b ) 2B mode, ( c ) 1T mode, ( d ) 2T mode, and ( e ) 1C mode More about this image found in Modal displacement of different axial locations: ( a ) 1B mode, ( b ) 2B mo...

Fig. 9 Corrected displacement of different modes at Sensor 1: ( a ) 1B mode, ( b ) 2B mode, ( c ) 1T mode, ( d ) 2T mode, and ( e ) 1C mode More about this image found in Corrected displacement of different modes at Sensor 1: ( a ) 1B mode, ( b )...

Fig. 10 Calibration factors predicted by proposed method More about this image found in Calibration factors predicted by proposed method

Fig. 11 Corrected and theoretical displacements of Sensors 2 and 3: ( a ) 1T mode, ( b ) 2T mode, and ( c ) 1C mode More about this image found in Corrected and theoretical displacements of Sensors 2 and 3: ( a ) 1T mode, ...