scholarly journals Finite element simulations of hyperpolarized gas DWI in micro‐CT meshes of acinar airways: validating the cylinder and stretched exponential models of lung microstructural length scales

2021 ◽  
Vol 86 (1) ◽  
pp. 514-525
Author(s):  
Ho‐Fung Chan ◽  
Guilhem J. Collier ◽  
Juan Parra‐Robles ◽  
Jim M. Wild
Keyword(s):  
Finite Element ◽  
Finite Element Simulations ◽  
Micro Ct ◽  
Length Scales ◽  
Stretched Exponential ◽  
Exponential Models ◽  
Hyperpolarized Gas

A Compliant Transmission Mechanism With Intermittent Contacts for Cycle-Doubling

2006 ◽  
Vol 129 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Nilesh D. Mankame ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Conceptual Design ◽  
Finite Element Simulations ◽  
Nonlinear Finite Element ◽  
Transmission Mechanism ◽  
Input Frequency ◽  
Length Scales ◽  
Wide Range ◽  
Macro Scale ◽  
Functional Prototype

A novel compliant transmission mechanism that doubles the frequency of a cyclic input is presented in this paper. The compliant cycle-doubler is a contact-aided compliant mechanism that uses intermittent contact between itself and a rigid surface. The conceptual design for the cycle-doubler was obtained using topology optimization in our earlier work. In this paper, a detailed design procedure is presented for developing the topology solution into a functional prototype. The conceptual design obtained from the topology solution did not account for the effects of large displacements, friction, and manufacturing-induced features such as fillet radii. Detailed nonlinear finite element analyses and experimental results from quasi-static tests on a macro-scale prototype are used in this paper to understand the influence of the above factors and to guide the design of the functional prototype. Although the conceptual design is based on the assumption of quasi-static operation, the modified design is shown to work well in a dynamic setting for low operating frequencies via finite element simulations. The cycle-doubler design is a monolithic elastic body that can be manufactured from a variety of materials and over a range of length scales. This makes the design scalable and thus adaptable to a wide range of operating frequencies. Explicit dynamic nonlinear finite element simulations are used to verify the functionality of the design at two different length scales: macro (device footprint of a square of 170mm side) at an input frequency of 7.8Hz; and meso (device footprint of a square of 3.78mm side) at an input frequency of 1kHz.

A Contact-Aided Compliant Mechanical Cycle-Doubler: Preliminary Analysis and Testing

2004 ◽  
Author(s):  
Nilesh D. Mankame ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Compliant Mechanism ◽  
Frequency Doubling ◽  
Finite Element Simulations ◽  
Nonlinear Finite Element ◽  
Input Frequency ◽  
Length Scales ◽  
Low Frequencies ◽  
Macro Scale ◽  
Explicit Dynamic

The performance of a contact-aided compliant mechanism that functions as a cycle doubler is studied in this paper via nonlinear finite element simulations. The topology of this mechanism was obtained from a systematic synthesis procedure and is reported elsewhere. Although the design was obtained for a quasi-static specification, the kinematic characteristics of the design suggest its ability to function adequately at low to moderate frequencies. The scalability of the design and its single-piece construction enable fabrication using different materials at various length scales. Therefore, it is possible to choose a scale and material combination that yields the frequency doubling action for various input frequencies. Explicit dynamic nonlinear finite element simulations are used to verify the functionality of the design at two different length scales: macro (device footprint of 289 sq. cm) corresponding to an input frequency of 20 Hz and meso (device footprint of a square of 14.3 sq. cm) corresponding to an input frequency of 1 kHz. Experiments on a macro scale prototype are used to validate the FE simulations for low frequencies.

Thermomechanical finite element simulations of ultrasonically assisted turning

2005 ◽  
Vol 32 (3-4) ◽  
pp. 463-471 ◽  
Author(s):  
A.V. Mitrofanov ◽  
V.I. Babitsky ◽  
V.V. Silberschmidt
Keyword(s):  
Finite Element ◽  
Finite Element Simulations

Mechanical Testing and Finite Element Simulations for the Use of Cellular Metals as Car Seat Components

2012 ◽  
Vol 83 (10) ◽  
pp. 972-980 ◽  
Author(s):  
Srecko Nesic ◽  
Klaus Unruh ◽  
Wilhelm Michels ◽  
Ulrich Krupp
Keyword(s):  
Finite Element ◽  
Mechanical Testing ◽  
Finite Element Simulations ◽  
Car Seat ◽  
Cellular Metals
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