Projects

In order to achieve highly ductile, extremely energy-absorbing material and structural behavior under impact stress, new material concepts and reinforcement types have to be developed. The basis of this development is strain-hardening short fiber reinforced concrete (SHCC) with a tensile elongation of more than 5% under quasi-static load as well as flat and spatial reinforcement structures from continuous fiber bundles (A1/I Development and evaluation of 3D reinforcing structures for structural strengthening against impact loading). The combination of textile structures and short fibers (hybrid fiber reinforcements) is also very promising (A3/I Development and characterization of hybrid-fiber reinforced composites for structural strengthening against impact loading). A goal-oriented design of the new composites’ properties under high strain rates is to be achieved by fundamental, multiscale, experimental and theoretical-numerical interdisciplinary investigations. The characterization of the new materials with predominantly anisotropic material behavior requires the design and implementation of new highly dynamic test and measurement techniques (A4/I Experimental characterization of the mechanical behavior of anisotropic and strain-hardening composites under impact loading, C1/I 3D measurement techniques of fracture processes). The experimental work will proceed together with the development of new numerical approaches such as the multiscale simulation of the anisotropic damping behavior of fiber reinforced concrete under impact in the fine mesoscale (B1/I Multi-scale simulation of the anisotropic damping properties of fiber-reinforced concrete under impact loading). The expansion of the developed numerical method by a bionic remodeling approach (B1/I Multi-scale simulation of the anisotropic damping properties of fiber-reinforced concrete under impact loading) is intended to allow the calculation of an optimal reinforcement orientation. The interphase design also plays an important role for the fiber-matrix composite (A2/I Strain-rate dependent composite behavior of fiber reinforcement in mineral-based matrices) which is favorable in terms of the fracture behavior. Furthermore, significant improvements are expected from higher heterogeneity or an engineered composition of the matrix (A3/I Development and characterization of hybrid-fiber reinforced composites for structural strengthening against impact loading). These conceptual-experimental developments are to be improved by the establishment of a physically motivated damage model for the description of the fiber pullout (B3/I Modeling textile reinforced components).
In the development of reinforcement solutions using new composites, variants for their application are considered both on the impact-facing side (A5/I Strengthening of plane RC elements against impact on the impact-far side) and on the impact-opposite side (A6/I Strengthening of plane RC elements against impact on the impacted side). Through this process natural principles of impact absorption with regard to their adaptability for reinforcement layers for structural components should be examined (A6/I Strengthening of plane RC elements against impact on the impacted side). The new impact-resistant composites and reinforcing systems should be developed and evaluated not only from an engineering but also from an economic and ecological point of view (C2/I Analysis and assessment of the sustainability and resilience of reinforcement methods with new composites).

Research Projects of GRK 2250/1

    
Micro Observation scale Macro
   
Material
Textile
3D textile structure
  A1/I Development and evaluation of 3D reinforcing structures for structural strengthening against impact loading  
    
Fiber
ESEM image showing fiber surrounded by cementitious matrix
A2/I Strain-rate dependent composite behavior of fiber reinforcement in mineral-based matrices     
  B2/I Modelling fiber-matrix bond and mineral-bonded composites under impact loading  
Composite
A cracked specimen of high-strength strain-hardening cement-based composites (SHCC) after being tested under tensile impact in the Hopkinson bar
A3/I Development and characterization of hybrid-fiber reinforced composites for structural strengthening against impact loading     
A4/I Experimental characterization of the mechanical behavior of anisotropic and strain-hardening composites under impact loading     
B1/I Multi-scale simulation of the anisotropic damping properties of fiber-reinforced concrete under impact loading   
 B3/I Modeling textile reinforced components 
Strengthened
structural
element
Bended reinforced conrete plate strengthened on the bottom side with a layer of SHCC showing the high flexural deformability of the strengthened element with no loss in load bearing capacity
 
     A5/I Strengthening of plane RC elements against impact on the impact-far side
     A6/I Strengthening of plane RC elements against impact on the impacted side
     B4/I Simulation of the failure of reinforced concrete structures under impact
 
     Experimental project        
     Numerical project        
     Interdisciplinary project        

Research Projects of GRK 2250/2

    
Micro Observation scale Macro
    
Material
Textile
3D textile structure
  A1/II Gradient 3D-reinforcing structures
with integrated in-situ sensors
  
    
Fiber
ESEM image showing fiber surrounded by cementitious matrix
A2/II Fiber and interphase
modification
     
A3/II Sustainable and impact-
resistant composites
     
Composite
A cracked specimen of high-strength strain-hardening cement-based composites (SHCC) after being tested under tensile impact in the Hopkinson bar
A4/II Shear resistance of mineral-
bonded composites
     
B1/II Multiscale simulation of the fracture
behavior of fiber-reinforced concrete
  
 B3/II Numerical multiscale analysis of hybrid
reinforced concrete
 
Strengthened
structural
element
Bended reinforced conrete plate strengthened on the bottom side with a layer of SHCC showing the high flexural deformability of the strengthened element with no loss in load bearing capacity
    A5/II Strengthening on the
rear side
     A6/II Damping layers as impact
strengthening
     B4/II Failure simulation of
strengthened structures
 
     Experimental project         
     Numerical project         
     Interdisciplinary project