Julendra Ariatedja
@its.ac.id
Department of Mechanical Engineering
Institut Teknologi Sepuluh Nopember
RESEARCH, TEACHING, or OTHER INTERESTS
Mechanical Engineering, Mechanics of Materials, Computational Mechanics, Ceramics and Composites
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Widyastuti, Fadhel Muhammad Yoga Fauzi, Wikan Jatimurti, Julendra Ariatedja, and Bambang Parmujati
AIP Publishing
Muhammad Burhanuddin, Widyastuti, and Julendra Bambang Ariatedja
AIP Publishing
Achmad Syaifudin, Julendra Bambang Ariatedja, and Katsuhiko Sasaki
Trans Tech Publications, Ltd.
During the implantation process, an expandable balloon stent undergoes a change in mesh shape with a high strain rate. Permanent mesh shape changes to the stents indicate plastic deformation has occurred. On a micro-scale, plastic deformation has significant influence when interacting with the soft tissue of human blood vessels. This experimental study aims to investigate the effect of surface treatment and cutting orientation on the changes in surface roughness that definitely occurs when a stent deployed. To study the effect of surface treatment, two types of surface treatment were applied after surface polishing, i.e. etching and electropolishing. Surface polishing is carried out to enable microscopic observation. As for examining the effect of cutting orientation, the plate is cut in lateral and longitudinal orientation against the predicted-rolling direction of 316L sheet-type of stainless steel. An intermittent tensile test is conducted to obtain information about the changes in surface roughness. The surface observation is carried out three times on a similar surface of testpiece after reaching plastic deformation. The experimental study shows that the orientation of raw material has an insignificant effect on the changes in stent surface roughness. As for the surface treatments, electropolishing tended to decrease the tensile property of material.
Achmad Syaifudin and Julendra B. Ariatedja
AIP Publishing
Considering the raw material of balloon-expandable stent that usually obtained from tube-type geometry, it is still unclear how the multilinear isotropic model obtained from flat-type specimen can be used to represent the actual behavior of stent expansion. In this experimental study, non-standard sheet-type and tube-type tensile test specimens are prepared, which are made from stainless steel 316L. To assure equality of both chemical composition, the testing is carried out using Optical Emission Spectrometer. For the tube-type (axial and tangential), three pieces of specimens are prepared for the tensile test. The forces and yielded elongations are recorded in order to generate stress-strain relationship. The study indicated that the correlation between the stresses and the strains was not similar among various geometry of specimens. Tangential tube-type specimen experienced increasing of total strain faster than other specimen type. It differed significantly compared to a sheet-type specimen. A moderate correlation between the stress and the strain is obtained by a axial tube-type specimen. This investigation suggested a new value of material properties obtained from tangential tube-type specimen to be used in the FE study of balloon-expandable stent.Considering the raw material of balloon-expandable stent that usually obtained from tube-type geometry, it is still unclear how the multilinear isotropic model obtained from flat-type specimen can be used to represent the actual behavior of stent expansion. In this experimental study, non-standard sheet-type and tube-type tensile test specimens are prepared, which are made from stainless steel 316L. To assure equality of both chemical composition, the testing is carried out using Optical Emission Spectrometer. For the tube-type (axial and tangential), three pieces of specimens are prepared for the tensile test. The forces and yielded elongations are recorded in order to generate stress-strain relationship. The study indicated that the correlation between the stresses and the strains was not similar among various geometry of specimens. Tangential tube-type specimen experienced increasing of total strain faster than other specimen type. It differed significantly compared to a sheet-type specimen. A moderate...
Achmad Syaifudin, Julendra B. Ariatedja, Yusuf Kaelani, Ryo Takeda, and Katsuhiko Sasaki
IOS Press
The utilization of Asymmetric stent for recovering atherosclerotic diseases, particularly non-symmetric obstruction, is a quite challenging breakthrough treatment. In terms of eccentric plaque, the non-uniform stiffness of arterial layer causes the increasingly complex issues of vulnerability. This study investigated the vulnerability of the interaction between the Asymmetric stent and the surrounding arterial layer using structural transient dynamic analysis in ANSYS. Four combinations of stent deployment, i.e. the Sinusoidal stent expanded by the offset balloon, the Sinusoidal stent expanded by the ordinary cylindrical balloon, the Asymmetric stent expanded by the offset balloon, and the Asymmetric stent expanded by the ordinary cylindrical balloon, are generated for this comparative study. Multilayer material properties from recent in vitro experiments are adopted for the surrounding arterial layer, such as a fibrous cap, lipid core, diseased-healthy intima, and diseased-healthy media. In order to address plaque vulnerability, the Cauchy stresses and Hencky strains are used for stress measure because of convenience in comparison with the uniaxial/biaxial tension test data. The location-specific threshold value from the diseased human carotid artery is adopted for rupture criteria. The simulation indicated that as regards the eccentric plaque, the plaque vulnerability is caused by the plaque shape and components rather than caused by the geometrical structure of the stent or balloon expansion method. Nevertheless, the non-symmetric inflation of balloon, which leads against the plaque, contributed to an increase in the vulnerability of fibrous cap of fibroatheroma plaque.
J.B. Ariatedja and O. Mamat
Science Alert