videos for tour 7 uploaded

891b7012 · Rostislav Chudoba · 4a278360 · 891b7012 · 891b7012 · 891b7012
Commit 891b7012 authored 2 years ago by Rostislav Chudoba
--- a/index.ipynb
+++ b/index.ipynb
@@ -317,18 +317,6 @@
    "[Pull out simulation using damage model](tour5_damage_bond/5_2_PO_cfrp_damage.ipynb)"
   ]
  },
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-   "cell_type": "markdown",
-   "metadata": {
-    "pycharm": {
-     "name": "#%% md\n"
-    }
-   },
-   "source": [
-    "<div style=\"background-color:lightgreen;text-align:left\"> <img src=\"icons/rest.png\" alt=\"Step by step\" width=\"40\" height=\"40\">\n",
-    "    &nbsp; &nbsp; <b>Our current location</b> </div>"
-   ]
-  },
  {
   "cell_type": "markdown",
   "metadata": {
@@ -365,6 +353,18 @@
    "[Localization and fracture energy](tour6_energy/6_3_localized_energy_dissipation.ipynb#top)\n"
   ]
  },
+  {
+   "cell_type": "markdown",
+   "metadata": {
+    "pycharm": {
+     "name": "#%% md\n"
+    }
+   },
+   "source": [
+    "<div style=\"background-color:lightgreen;text-align:left\"> <img src=\"icons/rest.png\" alt=\"Step by step\" width=\"40\" height=\"40\">\n",
+    "    &nbsp; &nbsp; <b>Our current location</b> </div>"
+   ]
+  },
  {
   "cell_type": "markdown",
   "metadata": {

 %% Cell type:markdown id: tags:

 # **Brittle-Matrix Composite Structures**

 Institute of Structural Concrete; @author: Rostislav Chudoba, Abedulgader Baktheer

 %% Cell type:markdown id: tags:

 ## BMCS landscape

 %% Cell type:markdown id: tags:

 | |   |   |   |
 |-|-|-------|------|
 | ![image-15.png](attachment:image-15.png) | ![image-4.png](fig/reinforcement.png)  | ![image-2.png](fig/bond.png) | ![image.png](fig/matrix.png) |
 | ![image-14.png](attachment:image-14.png) | [![image-6.png](fig/pullout.png)](pull_out/pull_out.ipynb) | ![image-7.png](fig/crack_bridge.png)| [![image-8.png](fig/mkappa.png)](mkappa/mkappa.ipynb) |
 | ![image-13.png](attachment:image-13.png)  | [![image-9.png](fig/tension.png)](pull_out/fragmentation.ipynb) | [![image-10.png](fig/bending.png)](bending/bending_3pt.ipynb) | ![image-11.png](fig/compression.png) |

 %% Cell type:markdown id: tags:

 ## Guided tours provided through BMCS landscape

 %% Cell type:markdown id: tags:

 | No. | Title |
 |- | - |
 | **[Tour 1:](#tour1)** | Mixture rule (effective composite stiffness) |
 | **[Tour 2:](#tour2)** | Constant bond (friction, pull-out, crack-bridge, multiple cracking) |
 | **[Tour 3:](#tour3)** | Nonlinear bond (hardening, softening -> failure modes: anchorage, cracing) |
 | **[Tour 4:](#tour4)** | Plastic bond behavior (irreversibility ->  energy dissipation) |
 | **[Tour 5:](#tour5)** | Damage bond behavior (2D sheet debonding) |
 | **[Tour 6:](#tour6)** | Energy supply, storage and dissipation |
 | **[Tour 7:](#tour7)** | Crack propagation in concrete |
 | **[Tour 8:](#tour8)** | Reinforced beam deflection - comparison wth EC2 and Model Code |

 %% Cell type:markdown id: tags:

 ## Knowledge and skills developed during the BMCS expedition

 %% Cell type:markdown id: tags:

 * Understand nonlinear material behavior, stress-redistribution, objectivity of material laws
 * Develop a basic understanding of damage, plasticity, fracture
 * Formulate simplified analytical models capturing material and structural behavior
 * Compare self-developed analytical models with general finite-element models
 * Distinguish model verification, calibration, validation and parametric studies

 %% Cell type:markdown id: tags:

 <a id="tour1"></a>
 ## **Tour 1**: Introduction

 ### 1.1 A roadmap through the BMCS landscape
 Topics, structure and organization of the course with a teaser about the thin concrete shells made of textile-reinforced concrete and oricrete.</br>
 [**Structure, method, teaser**](tour1_intro/1_1_roadmap.ipynb#top)

 ### 1.2 Introduction to Jupyter Lab and Notebooks
 Not only static slides and videos but also the possibility to interactively put your fingers on the theory in terms of prepared interactive applications is used throughout the course.
 <!-- Basic information how to
 use the `jupyter` notebooks are summarized here:</br>
 [**Web Apps:** first steps](link)
 -->
 [**Jupyter notebooks and Python**: short introduction, installation instructions](tour1_intro/1_2_jupyter_python.ipynb#top)

 ### 1.3 Interactive computational environment

 To demonstrate the theory on examples that can be interactively modified, let us consider an elementary case of mixture rule to determine the effective stiffness of an elastic composite </br>
 [**Mixture rule**: example elastic mixture rule](tour1_intro/1_3_elastic_stiffness_of_the_composite.ipynb#top)

 %% Cell type:markdown id: tags:

 <a id="tour2"></a>
 ## **Tour 2:** Constant bond - pull-out, crack bridge, fragmentation

 %% Cell type:markdown id: tags:

 ### 2.1 - Pull-out from rigid matrix - test setup and theory

 Using the analytical solution of the pullout problem assuming constant bond-slip law, elastic fiber and rigid matrix, we first explore the fundamental relations between the measured pull-out curve of a steel-rebar from the concrete matrix:</br>
 [**Pull-out:** analytical constant-bond model](tour2_constant_bond/2_1_1_PO_observation.ipynb#top)

 %% Cell type:markdown id: tags:

 ### 2.2 - Classification of pullout configurations with constant bond stress

 Include further configurations of a pull-out to show the differences in their behavior, learning the correspondence between the shape of the pull-out curve and the distribution of slip, shear, fiber and matrix strain and stresses depending on a particular configuration, i.e. elastic matrix, short fiber, short matrix and  clamped fiber:</br>
 [**Pull-out:** extended analytical constant-bond models - short / long / elastic / clamped](tour2_constant_bond/2_2_1_PO_configuration_explorer.ipynb#top)

 %% Cell type:markdown id: tags:

 ### 2.3 - Multiple cracking - fragmentation

 The crack-bridging action of a fiber within a composite loaded in tension is a key to understanding the behavior of brittle-matrix composites. By putting crack bridges in a series, we can directly simulate a tensile test and predict the test response in terms of the stress-strain and crack spacing curves. This helps us to study and understand the relation between reinforcement ratio, bond strength, matrix strenth and the tensile response of the composite:
 </br>
 [**Multiple cracking:** tensile response of a composite](tour2_constant_bond/fragmentation.ipynb#top)

 %% Cell type:markdown id: tags:

 <a id="tour3"></a>
 ## **Tour 3:** Non-linear bond-slip law

 ### 3.1 - Pull-out with softening and hardening bond behavior

 The shape of the bond-slip law is distinguished into hardening and softening leading to a completely different pull-out behavior. A numerical model of the pull-out test is used to monitor and explain the debonding process in two studies for steel and CFRP bond to concrete showing a qualitatively different behavior.</br>
 [**Pull-out**: with softening and hardening](tour3_nonlinear_bond/3_1_nonlinear_bond.ipynb#top)

 %% Cell type:markdown id: tags:

 ### 3.2 - Effect of bond length: anchorage versus pull-out failure

 With the developed understanding, we address questions related to design rules: What is the necessary bond length to avoid or to deliberately induce a fiber pull-out or fiber rupture. At which distance from the loaded end can we expect a matrix crack to appear?</br>
 [**Anchorage**: pull-out, fiber rupture, matrix crack](tour3_nonlinear_bond/3_2_anchorage_length.ipynb#top)

 ### Related optional support material
 The numerical vehicles used in the above two trips are provided here in a more detail as a bonus material.</br>
 [**Appendix**: Newton iterative scheme](extras/newton_method.ipynb#top)</br>
 [**Appendix**: Nonlinear finite-element solver for 1d pullout](extras/pullout1d.ipynb#top)

 %% Cell type:markdown id: tags:

 <a id="tour4"></a>
 ## **Tour 4:** Irreversibility due to yielding

 ### 4.1 - Unloading and reloading

 Non-linear behavior can be described by nonlinear functions as we did so far. However,
 this description cannot capture the irreversible changes within the material structure.
 To demonstrate this, let us revisit the pull-out tests and consider a loading scenario with unloading and reloading.</br>
 [Unloading with multi-linear bond-slip law](tour4_plastic_bond/4_1_PO_multilinear_unloading.ipynb#top)

 ### 4.2 - The basic concept of plasticity

 The first option in describing irreversible changes in a material point is the
 plasticity. The stick-slip interface represents the simplest possible
 type of plastic behavior that can be conveniently used to explain the key concept
 behind all material models introducing plastic behavior.</br>
 [Ideal, isotropic and kinematic hardening of an interface](tour4_plastic_bond/4_2_BS_EP_SH_I_A.ipynb#top)

 %% Cell type:markdown id: tags:

 ### 4.3 - Cyclic pullout test and plastic material behavior

 With the knowledge of the plasticity at a material point level, let us study the effect of unloading and reloading at the level of a structure. In particular, we learn to interpret the meaning of the unloading stiffness at the level of a structure.</br>
 [Cyclic pullout of textile fabrics and CFRP sheets](tour4_plastic_bond/4_3_PO_trc_cfrp_cyclic.ipynb#top)

 %% Cell type:markdown id: tags:

 <a id="tour5"></a>
 ## **Tour 5:** Irreversibility due to damage

 ### 5.1 Damage initiation, damage evolution, 2D bond behavior

 We are going to define several damage functions which are used in damage models available in finite element codes. Their definition is based on an assumed profile of breakage propagation. The derived damage functions are then used to model a two-dimensional interface with slip and shear stress defined as a vector.</br>
 [Damage initiation, damage evolution, 2D bond behavior](tour5_damage_bond/5_1_Introspect_Damage_Evolution_Damage_initiation.ipynb)

 ### 5.2 Pullout behavior governed by damage [in production]

 Application of the damage model to pullout test is used to discuss general aspects of damage models applied in finite element calculations.</br>
 [Pull out simulation using damage model](tour5_damage_bond/5_2_PO_cfrp_damage.ipynb)

 %% Cell type:markdown id: tags:

-<div style="background-color:lightgreen;text-align:left"> <img src="icons/rest.png" alt="Step by step" width="40" height="40">
-    &nbsp; &nbsp; <b>Our current location</b> </div>
-
-%% Cell type:markdown id: tags:
-
 <a id="tour6"></a>
 ## **Tour 6:** Energy and fracture

 ### 6.1 Energy flow - supply, storage, dissipation

 Inelastic deformation induces energy dissipation. By distinguishing stored and lost energy within a system we can provide another physical perspective to the changes in the material structure.</br>
 [Energy games](tour6_energy/6_1_energy_dissipation.ipynb#top)

 ### 6.2 Frictional pullout and energy dissipation

 The analytical solution of the pullout test provides a suitable model to demonstrate the evaluation of the energy dissipation within an initial boundary value problem with including an inelastic deformation.</br>
 [Frictional pullout and energy dissipation](tour6_energy/6_2_Energy_released_in_pullout_constant_bond_and_rigid_matrix.ipynb#top)

 %% Cell type:markdown id: tags:

 ### 6.3 Localization and fracture energy

 Application of the local energy evaluation scheme to the pullout simulation with softening behavior provides us a clear interpretation of fracture energy</br>
 [Localization and fracture energy](tour6_energy/6_3_localized_energy_dissipation.ipynb#top)

 %% Cell type:markdown id: tags:

+<div style="background-color:lightgreen;text-align:left"> <img src="icons/rest.png" alt="Step by step" width="40" height="40">
+    &nbsp; &nbsp; <b>Our current location</b> </div>
+
+%% Cell type:markdown id: tags:
+
 <a id="tour7"></a>
 ## **Tour 7:** Bending and crack propagation

 ### 7.1 Notched beam with straight crack propagation

 With the possibility to evaluate energy dissipation, we study the crack propagation
 in a notched bending test using a finite-element model. This study presents the reasoning behind
 the identification of fracture energy using the notched bending test.
 At the same time, it illuminates how to correctly reflect the crack localization
 in the standard finite-element method.</br>
 [Propagation of a straight crack](tour7_cracking/7_1_bending3pt_2d.ipynb#top)

 %% Cell type:markdown id: tags:

 ### 7.2 Experimental identification of fracture energy and size effect

 The explained correspondence between work supplied to the test and the energy dissipation is exploited to design a simple test setup delivering an estimate of the fracture energy as a fundamental characteristic of concrete behavior. The important consequence of localization behavior inducing a so called size effect is presented using a simple parametric study.</br>
 [Fracture energy and size effect](tour7_cracking/7_2_fracture_energy_ident.ipynb#top)

 %% Cell type:markdown id: tags:

 <a id="tour8"></a>
 ## **Tour 8:** Reinforced bended cross section

 ### 8.1 Moment-curvature derived for arbitrary cross-sectional layout

 The behavior of a reinforced cross section can be characterized using
 a nonlinear moment-curvature relation. This relation describes the effect
 of multiple cracking and debonding in the tensile, crack bridging action
 including debonding, and nonlinear response of concrete in the compression zone.</br>
 [Nonlinear moment-curvature relation](tour8_rcbeam/8_1_rc_beam_mkapa.ipynb#top)

 ### 8.2 Load deflection curve of reinforced concrete beam

 The description of the stress redistribution due to cracking, debonding and
 concrete yielding under compression within the moment-curvature relation
 can be used for a very efficient assessment of maximum beam deflection
 or column stability. An efficient evaluation procedure can be used to cover
 a broad application spectrum and to generate general design formulas for
 serviceability limit state design.</br>
 [From a model to a design rule](tour8_rcbeam/8_2_rc_beam_uls_sls.ipynb#top)

 %% Cell type:markdown id: tags:

 <a id="tour9"></a>
 ## **Tour 9:** Retrospective, summary of questions

 %% Cell type:code id: tags:

 ``` python
 ```

--- a/tour7_cracking/7_1_bending3pt_2d.ipynb
+++ b/tour7_cracking/7_1_bending3pt_2d.ipynb
--- a/tour7_cracking/7_2_fracture_energy_ident.ipynb
+++ b/tour7_cracking/7_2_fracture_energy_ident.ipynb
--- a/tour8_rcbeam/8_2_rc_beam_uls_sls.ipynb
+++ b/tour8_rcbeam/8_2_rc_beam_uls_sls.ipynb