adina混凝土结构例子

jacobi

adina官网的例子，
不知哪个大拿可以实现出来，
感觉adina太牛了，这么粗糙的网格，
居然还可以计算开裂。
不知道这个是否需要最新的版本才能实现。


谢谢




Modeling Concrete in ADINA Concrete is a very important material and present all around us, in concrete bridges, dams, buildings, and so on. Hence it is important to be able to model a concrete material adequately in finite element analyses. However, concrete is a most complex material to model in analysis. Many research efforts have been conducted on understanding the behavior of concrete, and numerous papers have been published on modeling concrete for numerical simulations. When subjected to very small stresses, the material behaves linearly, and elastically, but beyond certain threshold values, we observe cracking in tension, with thereafter tension softening, crushing in compression, and all in a highly nonlinear manner. This complex behavior of concrete must be represented in general nonlinear analyses, for example for structures under earthquake loading, or in accident conditions. To capture this behavior for analysis purposes, a microstructural representation shows most potential but such modeling of concrete is still not possible for large-scale structural analyses. Hence, many researchers have pursued a phenomenological approach in which the material behavior is represented by nonlinear stress-strain curves and failure surfaces that can be highly complex. In addition to having a model that represents the material behavior adequately, the finite element procedures to analyse concrete structures must be reliable and efficient. Since the solution response can be highly nonlinear, the iterative schemes used in static and implicit dynamic solutions must converge when cracking, crushing and softening of a finite element model occurs. There is probably no single concrete material model now available that can be universally applied, efficiently in practice, to model any concrete material and under any loading conditions (namely static, slow dynamic and fast dynamic conditions). The microstructure of concrete materials is too complex. Hence, until such model is available and finite element programs can use the model efficiently in practical large-scale analyses, it is appropriate to offer a number of concrete models in a computing environment. A powerful concrete material model has been available in ADINA for many years, and has been used widely in numerous applications, see Reference 1. However, as mentioned, since concrete is a complex material, there is need for other models. In particular, simple models that however capture the major characteristics of concrete behavior for certain analyses are very desirable. The additional ADINA concrete model now available is such a model, indeed only a single material parameter is to be input — the uniaxial compressive strength. The model is based on the work described in References 2 and 3. The salient features of the model are given by experimental data that suggest —

• The material behavior in compression is nonlinear up to a limit point followed by a brittle post-peak behavior, which is characterized by a complete and immediate loss of load-carrying capacity after the ultimate strength is attained
  
• The material cannot be considered to be a continuum beyond its peak load level
  
• Microcracking processes define the compressive behavior of concrete up to failure while macrocracking describes the fracture processes occurring during failure
  
• Failure can be captured in the stress space via a three-dimensional failure surface
  
• All material constants can be related to the uniaxial compressive strength of a cylinder specimen
  
  

In consideration of the test results and analytical work, the additional ADINA concrete model is based on —

• a nonlinear experimentally-based stress-strain law for the behavior in compression and tension as shown in Figure 1,
  
• an experimentally-based stress failure surface that dictates when either cracking or crushing occurs in concrete, see Figure 2, and
  
• a post-failure response for cracking based on a smeared crack approach that allows cracks to close and reopen.
  
  

Figure 1  Stress-strain behavior of the data fitted concrete material model





Figure 2  Failure surface of the data fitted concrete material model


Since the model is, in essence, based on fitting laboratory test results, we refer to the model as the data fitted concrete model (or in short, DF-concrete model). The model is not applicable to any concrete structural analysis — and indeed is directed to static and low frequency dynamic conditions (as typically found in earthquake loadings) — but can be very simple to use and effective. Figure 3 shows a schematic of a gravity concrete dam analyzed by A. Carpinteri et. al. [4] and Figure 4 gives the 3D finite element mesh representing the structure. The calculated load-displacement response using the DF-concrete model is shown in Figure 5.

Figure 3  Concrete gravity dam from A. Carpinteri et. al.		Figure 4  Finite element mesh of the gravity dam

Figure 5  Crack mouth opening displacement (CMOD) calculated using the DF-concrete model in ADINA compared to experimental results and results from Carpinteri



Figure 5 also shows a comparison solution given in Reference 4. The ADINA DF-concrete model predicts the crack mouth opening displacement, CMOD, in good agreement with the experimental result. The movie below shows the propagation path of the cracks as the loading is increased.





The movie at the top shows the development of cracks in a reinforced concrete beam solved with the DF-concrete model until its collapse. While the long-time available ADINA concrete material model has been amply used in many complex concrete structural analyses, this additional DF-concrete model will surely increase the applicability of ADINA in this very interesting and difficult field.

lynnxiong

弥散性裂缝模型啊，粗糙一点也没关系，反正也算不出开裂宽度

anjing8811

弥散裂缝好像也可以算裂缝宽度吧。  我想可能用了高阶单元。

anjing8811

例子算的比较准，而且收敛性比较好。有点不可思议啊， 不知处理其他的混凝土问题怎么样？ 关于混凝土方面的子程序怎么样？