{"title":"Kármán and the development of the material models of concrete","authors":"A. Windisch","doi":"10.32970/CS.2019.1.1","DOIUrl":null,"url":null,"abstract":"The failure models developed until the 1960ies were defined by the testing equipment: the triaxial loading cell which was developed at the beginning of the last century by Karman. The axial loading was performed with a solid loading plate, the central-symmetric transverse loading through hydraulic pressure. Therefore, the characterization of the failure surface with the hydrostatic normal stress and octahedral shear stress without any reference to deformations was a logical consequence. In 1963 Hilsdorf proposed a brush-type loading equipment. Using brushes Kupfer carried out his wellknown biaxial loading tests which made possible the characterization of concrete strength by means of the principal stresses. In 1977 Ottosen applied in his model for multiaxial strength of concrete the stress invariants. The same did CEB in the Bulletin d’Information N°. 156. Van Mier (1984) applied brushes and proposed a 3D-type representation using contour lines. The MC2010 returned to the Ottosen model and declared concrete as frictional material. Using the principal stresses, a new, transparent (and physically really sound) form of representation of the failure surface showing the strength increase due to bi- and triaxial loading is presented.","PeriodicalId":87278,"journal":{"name":"International journal of concrete structures & materials","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2019-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International journal of concrete structures & materials","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.32970/CS.2019.1.1","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The failure models developed until the 1960ies were defined by the testing equipment: the triaxial loading cell which was developed at the beginning of the last century by Karman. The axial loading was performed with a solid loading plate, the central-symmetric transverse loading through hydraulic pressure. Therefore, the characterization of the failure surface with the hydrostatic normal stress and octahedral shear stress without any reference to deformations was a logical consequence. In 1963 Hilsdorf proposed a brush-type loading equipment. Using brushes Kupfer carried out his wellknown biaxial loading tests which made possible the characterization of concrete strength by means of the principal stresses. In 1977 Ottosen applied in his model for multiaxial strength of concrete the stress invariants. The same did CEB in the Bulletin d’Information N°. 156. Van Mier (1984) applied brushes and proposed a 3D-type representation using contour lines. The MC2010 returned to the Ottosen model and declared concrete as frictional material. Using the principal stresses, a new, transparent (and physically really sound) form of representation of the failure surface showing the strength increase due to bi- and triaxial loading is presented.
直到20世纪60年代发展起来的破坏模式都是通过测试设备来定义的:上世纪初由卡门公司开发的三轴加载箱。轴向加载采用固体加载板,中心对称横向加载采用液压加载。因此,在不考虑变形的情况下,用静水法向应力和八面体剪应力来表征破坏面是顺理成章的。1963年希尔斯多夫提出了一种刷式装载设备。Kupfer使用刷子进行了他著名的双轴加载试验,这使得通过主应力来表征混凝土强度成为可能。1977年,奥托森在他的混凝土多轴强度模型中应用了应力不变量。行政首长协调会在《新闻公报》中也做了同样的工作。156. Van Mier(1984)使用笔刷,并提出了使用等高线的3d型表示。MC2010回到Ottosen模型,并宣布混凝土为摩擦材料。利用主应力,提出了一种新的、透明的(物理上真正合理的)破坏面表示形式,显示了由于双轴和三轴加载而导致的强度增加。