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  <doc>
    <id>2161</id>
    <completedYear/>
    <publishedYear>2020</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>30</pageLast>
    <pageNumber/>
    <edition/>
    <issue>12</issue>
    <volume>15</volume>
    <type>article</type>
    <publisherName>PLOS</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Computational analysis of the effects of geometric irregularities and post-processing steps on the mechanical behavior of additively manufactured 316L stainless steel stents</title>
    <abstract language="eng">Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41% in the as-built and by 59% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures.</abstract>
    <parentTitle language="eng">PLoS ONE</parentTitle>
    <identifier type="doi">10.1371/journal.pone.0244463</identifier>
    <note>Corresponding author: Lisa Wiesent</note>
    <enrichment key="BegutachtungStatus">peer-reviewed</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Lisa Wiesent</author>
    <author>Ulrich Schultheiß</author>
    <author>Philipp Lulla</author>
    <author>Ulf Noster</author>
    <author>Thomas Schratzenstaller</author>
    <author>Christof Schmid</author>
    <author>Aida Nonn</author>
    <author>Ashley Spear</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Heat treatment</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Lasers</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Surface treatments</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Specimen preparation and treatment</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Material properties</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Stiffness</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Deformation</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Powders</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>swd</type>
      <value>Koronarendoprothese</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>swd</type>
      <value>Rapid prototyping</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>swd</type>
      <value>Numerische Methode</value>
    </subject>
    <collection role="ddc" number="610">Medizin und Gesundheit</collection>
    <collection role="institutes" number="FAKMB">Fakultät Maschinenbau</collection>
    <collection role="institutes" number="RCBE">Regensburg Center of Biomedical Engineering - RCBE</collection>
    <collection role="oaweg" number="">Gold Open Access- Erstveröffentlichung in einem/als Open-Access-Medium</collection>
    <collection role="persons" number="schratzenstallermd">Schratzenstaller, Thomas (Prof. Dr.) -Labor Medizinprodukte</collection>
    <collection role="institutes" number="TCNeustadt">Technologie-Campus Neustadt an der Donau</collection>
    <collection role="persons" number="nonncmm">Nonn, Aida (Prof. Dr.) - Computational Mechanics and Materials Lab</collection>
    <collection role="persons" number="tcnehno">Technologie-Campus Neustadt a. d. Donau (Prof. Ehrlich+ Prof. Nonn)</collection>
    <collection role="othforschungsschwerpunkt" number="16314">Lebenswissenschaften und Ethik</collection>
    <collection role="oaweg" number="">Corresponding author der OTH Regensburg</collection>
    <collection role="institutes" number="TCParsberg">Technologie-Campus Parsberg-Lupburg</collection>
    <collection role="institutes" number="">Labor Medizinprodukte</collection>
    <collection role="institutes" number="">Computational Mechanics and Materials Lab (CMM)</collection>
    <collection role="institutes" number="">Labor Werkstoffrandschichtanalytik</collection>
  </doc>
</export-example>
