{"title":"Omni first-ply-failure envelopes — A conservative approach to assess laminate failure","authors":"Erik Kappel","doi":"10.1016/j.jcomc.2024.100460","DOIUrl":null,"url":null,"abstract":"<div><p>Omni first-ply-failure (FPF) envelopes are an elegant yet conservative approach to assess composite laminate failure on a global level. Omni envelopes can be found increasingly in recent publications. However, the development process of those envelopes shows a lack of clarity. At some point the illustration switches from a laminate-strain basis <span><math><mrow><mo>(</mo><msub><mrow><mi>ɛ</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>,</mo><msub><mrow><mi>ɛ</mi></mrow><mrow><mi>y</mi></mrow></msub><mo>,</mo><msub><mrow><mi>γ</mi></mrow><mrow><mi>x</mi><mi>y</mi></mrow></msub><mo>)</mo></mrow></math></span> to the particular case of laminate principal-strain <span><math><mrow><mo>(</mo><msub><mrow><mi>ɛ</mi></mrow><mrow><mi>I</mi></mrow></msub><mo>,</mo><msub><mrow><mi>ɛ</mi></mrow><mrow><mi>I</mi><mi>I</mi></mrow></msub><mo>)</mo></mrow></math></span> basis. The latter is elegant, as the principal-strain space can be easily plotted in 2D. This article presents two procedures to directly determine omni FPF envelopes and it clarifies the transfer to principal strains.</p><p>While the Tsai–Wu criterion is used in almost all available publications, the present article uses Cuntze’s failure mode concept (FMC). The article provides a simple example case, which demonstrates the application of omni envelopes in context of FEA based CFRP design.</p></div>","PeriodicalId":34525,"journal":{"name":"Composites Part C Open Access","volume":null,"pages":null},"PeriodicalIF":5.3000,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666682024000318/pdfft?md5=769bb38841754ede7fbceb081acf3edc&pid=1-s2.0-S2666682024000318-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Composites Part C Open Access","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666682024000318","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, COMPOSITES","Score":null,"Total":0}
引用次数: 0
Abstract
Omni first-ply-failure (FPF) envelopes are an elegant yet conservative approach to assess composite laminate failure on a global level. Omni envelopes can be found increasingly in recent publications. However, the development process of those envelopes shows a lack of clarity. At some point the illustration switches from a laminate-strain basis to the particular case of laminate principal-strain basis. The latter is elegant, as the principal-strain space can be easily plotted in 2D. This article presents two procedures to directly determine omni FPF envelopes and it clarifies the transfer to principal strains.
While the Tsai–Wu criterion is used in almost all available publications, the present article uses Cuntze’s failure mode concept (FMC). The article provides a simple example case, which demonstrates the application of omni envelopes in context of FEA based CFRP design.