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- Constitutive equation (3)
- Fire (3)
- Creep (2)
- Acoustic emission (1)
- Carbon fibre reinforced plastics CFRP (1)
- Circular (1)
- Column (1)
- Columns (1)
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- Concentrically braced steel frames (1)
- Concrete (1)
- Concrete filled tube (CFT) column (1)
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- Endochronic plasticity (1)
- Finite element method (1)
- Finite element model (1)
- Fire after earthquake (1)
- Fire engineering (1)
- Fire following earthquake (1)
- Fire performance (1)
- Fire resistance (1)
- Fully developed fire (1)
- Gas pore pressure (1)
- High performance concrete (1)
- High temperature (1)
- High temperatures (1)
- High-Throughput Fire Tests (1)
- High-performance concrete (HPC) (1)
- Hybrid testing (1)
- Intermediate-scale test method (1)
- Intumescent coatings (1)
- Large-scale tests (1)
- Ordinary concrete (1)
- Pseudo-dynamic testing (1)
- Restraining (1)
- Seismically damaged column (1)
- Spalling (1)
- Steel (1)
- Structural integrity investigation (1)
- Substructuring (1)
- Thermal cracking (1)
- Thermal strain (1)
- Thermo mechanical stresses (1)
- UMAT (1)
- Ultrasonic testing (1)
- Viscoplasticity (1)
- Weathering (1)
- composite (1)
- fire resistance (1)
- fire stability (1)
- intermediate-scale testing (1)
- sandwich panels (1)
- shells (1)
Organisationseinheit der BAM
High-throughput fire tests and weathering-induced degradation behaviour of intumescent coatings
(2018)
In this work, the weathering-induced degradation of intumescent coatings was investigated by a systematic and comprehensive approach. A mechanism is revealed that is proposed to be responsible for the loss of function of intumescent coatings induced by weathering.
First, the thermal decomposition of artificially weathered intumescent coatings was examined. To get a better understanding of the weathering and ageing phenomena, the degradation behaviour of the single ingredients during the weathering process was investigated, as well as their chemical and physical interactions. For the systematic approach, the materials that are essential for intumescence (ammonium polyphosphate, pentaerythritol, titanium dioxide, melamine and the binder) are treated with moisture, elevated temperature and UV radiation.
Thermogravimetry (TG) and IR spectroscopy were used to compare the initial samples with their different grades of weathering. We demonstrate that ammonium polyphosphate, melamine and the binder are mainly responsible for the ageing process. Further, it was demonstrated that TG and IR spectroscopy are suitable measuring methods to detect the effects of weathering on intumescent coatings.
Finally, a small-scale fire test procedure is introduced. Based on the reduction of the sample size, up to 50 samples can be tested in a single fire test. The results of this fire test have the same quality as the results from standard intermediate fire tests corresponding to DIN 4102-8.
Experimental and numerical study of high performance concrete columns subjected to fire loading
(2009)
Damage and strength reduction of a high performance concrete due to thermomechanical stresses
(2008)
An intermediate-scale fire testing approach on the structural integrity of lightweight materials
(2013)
Carbon or glass über composites and Sandwich structures, the lightweight materials of choice for aviation, naval, offshore and construction show an enormous energy saving potential. Their combination of excellent specific mechanical properties, high corrosive resistance and thermal insulation properties in combination with various adoptable fabrication techniques leading to mass and fuel cost reduction. The most limiting single factor for a wider use of fibre reinforced plastics (FRP) in particular as elements for structural application is believed to be their fire behaviour (Mouritz and Gibson, 2006). FRPs promote burning by themselves consuming the stabilizing polymeric matrix while embedded fibers (glass, carbon) persisting the flame (Mouritz et ah, 2006). Already at elevated temperatures (100 - 200 °C) the matrix softens with a loss in mechanical properties (Perret et al., 2011, Mouritz and Gibson, 2006). For this reason the stability of the structural component is decreased severely. Fire behavior becomes the major hazard to worry about, increasingly demanding targetoriented investigation, suitable testing and tailored development.
Experimental approaches in the bench-scale have been proposed to investigate the structural integrity in the past (La Delfa et al., 2009, Gibson et al., 2010, Seggewiß, 2011, Mouritz and Gardiner, 2002, Schartel et al.). Ascribed to the small-scale neither the mechanical properties nor the effects of fire may be represented satisfactorily. Flence, the task is to perform more realistic investigations under adequate compressive loads in fully developed fires, based on suitable specimen sizes. Also (La Delfa et al., 2009)) have announced that it is evident that larger scale test of composites are needed. The aim of this study is to present a developed intermediate-scale test setup to perform more realistic investigations (Hörold et al.). Mechanical loading is generated by a column furnace in terms of compression due to a more severe response of specimens in fire tests (Seggewiß, 2011, Gibson et al., 2012, Feih et al., 2008, Feih et al., 2007). An oil burner used to determine the burnthrough resistance of thermal/acoustic insulation materials provides fire directly onto one side of the specimen (Federal Aviation Administration, 2003). Generating a fully developed fire the NexGen burner offers a homogenous heat flux of ~ 180 kW/m2. The intermediate-scale is addressed by specimen sizes either 500 x 500 mm or 1000 x 500 mm with a maximum thickness of 50 mm. The specimen attachment is realized by a compression device that was designed to apply the compressive loads, figure 1. The test setup for specimens with component like dimensions allows realistic investigations up to structural failure in absence and presence of fire load. A first test series was carried out with different levels of loading while the fire remained unchanged. Failure mechanisms, temperature distributions, diversity of FRPs regarding fiber, matrix, lay-up and core as well as flame retardant Systems are in the scope of investigation.
Substrukturtechnik - eine hybride Prüfmethode ; Überblick mit Anwendung im Brandingenieurwesen
(1999)
The phenomenon of creep of structural steel in fire engineering is gaining more and more interest. Due to shortcomings of the EC3 constitutive model and other approaches based on classical creep theory an alternative approach mainly based on the ideas of Krempl is proposed. Due to this so-called operator approach the material as well as the constitutive model is looked upon as an operator. The application of this view serves as a guide through the analysis of the relationship between experimental facts and constitutive theory especially in the context of transient creep.