June 1, 2019 by admin 0 Comments

Characterization of the biomechanical properties of canine trachea using a customized 3D-printed apparatus

Authors
Jennifer Sang-jee Lee (a, 1), Jonghyun Park (b, 1), Dong-A Shin (b), Yoon-jong Ryu (a), Hee Chan Kim (c, d, e), Jung Chan Lee (c, d, e), Seong Keun Kwon (a)
Abstract
Objectives The canine trachea is considered to be an excellent preclinical model for tracheal research due to its similar mechanical and dimensional characteristics to the human trachea. However, normative biomechanical properties have yet to be defined and it is one of the main reasons tracheal reconstruction has not succeeded in animal models at large scale. Variation and inaccurate measurement due to a lack of proper apparatus for mechanical tests further prevent determination of normative mechanical data of the trachea. The goal of this study was to overcome these shortcomings by designing the measuring apparatus using 3D-printing technology. Using this apparatus, we determined the normative biomechanical properties of the canine trachea. Methods Whole tracheas were obtained from thirteen mongrel dogs. Biomechanical measurements were performed to determine the radial compressive strength and tensile strength of the intact trachea, and the elastic modulus of the tracheal cartilage. Results Structural parameter data indicated the canine trachea to have inner-diameters similar to those of the human trachea and other widely used animal models. The compressive strength was 4.24 N while the tensile strength was 29.96 N. The elastic modulus of the cartilage portion of the trachea was 1.58 N without showing a significant difference in value based on the location of the trachea. Conclusions This study delineates a comprehensive and foundational characterization of the biomechanical properties of both the intact and cartilage portion of the canine trachea. The parameters were in agreement with those of the human trachea, confirming the canine trachea to be an excellent preclinical model for tracheal research.

May 3, 2019 by admin 0 Comments

Analytical study on the 3D-printed structure and mechanical properties of basalt fiber-reinforced PLA composites using X-ray microscopy

Authors
Siwon Yu (a, b), Yun Hyeong Hwang (b), Jun Yeon Hwang (b), Soon Hyung Hong (a)
Abstract
A high-resolution X-ray microscope was used to quantitate the internal morphological characteristics of 3D-printed, basalt-fiber-reinforced PLA composites. 3D-printed composites have microstructures and mechanical properties that are distinct from those of conventional mold-pressed composites. One such distinction lies in the presence of voids, which form naturally during 3D printing. All of the composite components, including the fiber, the matrix, and the aforementioned voids were oriented parallel to the printing direction. The mechanical properties of the final composites were also greatly impacted by their microstructural characteristics, including fiber length, fiber orientation, and the presence of voids. It was also confirmed that the voids generated during the 3D printing process can be classified into two types (inter- and inner-filament voids), whose shapes, sizes, and distributions are completely different from each other, and that they clearly have a decisive influence on the remarkable differences in the strength of the composites.