Determination of compressive strength of unidirectional composites by three-point bending tests

2009 ◽  
Vol 28 (2) ◽  
pp. 150-156 ◽  
Author(s):  
N. Carbajal ◽  
F. Mujika
Keyword(s):  
Compressive Strength ◽  
Bending Tests ◽  
Unidirectional Composites ◽  
Three Point Bending

Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

2012 ◽  
Vol 12 (2) ◽  
pp. 186-194 ◽  
Author(s):  
Oldřich Sucharda ◽  
David Mikolášek ◽  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Concrete Beams ◽  
Linear Analysis ◽  
Bending Tests ◽  
Cube Strength ◽  
Non Linear ◽  
Compressive Strength Of Concrete ◽  
Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

Fracture Toughness and Cracking Behaviour of SCC Compared to VC

2013 ◽  
Vol 577-578 ◽  
pp. 205-208
Author(s):  
Sara Korte ◽  
Veerle Boel ◽  
Wouter de Corte ◽  
Geert de Schutter
Keyword(s):  
Fracture Toughness ◽  
Fracture Process ◽  
Critical Value ◽  
Fracture Parameter ◽  
Self Compacting Concrete ◽  
Bending Tests ◽  
Three Point Bending ◽  
Notched Specimens ◽  
Subsequent Determination

Vibrated concrete (VC) and self-compacting concrete (SCC) have a substantially different composition, resulting in dissimilar mechanical properties regarding cracking behaviour. The critical value of the mode I stress-intensity factor KICis an appropriate fracture parameter for evaluating fracture toughness and can be obtained from three-point bending tests (3PBT) on small, notched specimens. Subsequent determination of the energy release rate thus allows to examine the crack propagation and fracture process of both concrete types. This paper describes the results of such 3PBTs on samples, made from VC and SCC. Evaluation of the cracking behaviour, derived from these results, reveals remarkable differences.

Flexural Properties of Polyamides: Influence of Strain Rate, Friction and Moulding-Induced Anisotropy

2014 ◽  
Vol 601 ◽  
pp. 29-32
Author(s):  
Dan Andrei Serban ◽  
Tudor Voiconi ◽  
Liviu Marsavina ◽  
Vadim V. Silberschmidt
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Tensile Tests ◽  
Flexural Properties ◽  
Induced Anisotropy ◽  
Flexural Behaviour ◽  
Bending Tests ◽  
Three Point Bending ◽  
Cooling Conditions

In recent years, advances in material testing equipment caused the determination of mechanical properties by means of three-point bending tests to lose ground in detriment to more accurate tensile tests. However, if components undergo bending deformation in service, the identification of the materials flexural behaviour is essential. The investigated material is a thermoplastic polymer, test specimens being cut in prismatic shapes from injected sheets, which present a variation in properties due to cooling conditions. This paper presents results of three-point bending tests with emphasis on the influence of strain rate and anisotropy on flexural strength and chord modulus. Results show an increase in flexural properties with strain rate and a considerable influence of anisotropy on mechanical properties.

An Improved Procedure for the Determination of the Elastic Constants of Component-Lead-Board Assemblies

1991 ◽  
Vol 113 (4) ◽  
pp. 427-430 ◽  
Author(s):  
T. S. Chang ◽  
Edward B. Magrab
Keyword(s):  
Elastic Constants ◽  
Orthotropic Plate ◽  
Torsion Test ◽  
Least Square ◽  
Bending Test ◽  
Beam Model ◽  
Bending Tests ◽  
Three Point Bending ◽  
Least Square Procedure

An improved means of obtaining the elastic constants of component-lead-board assemblages from two three-point bending tests and one four-point torsion test is proposed. The suggested method models the three-point bending test as an orthotropic plate and uses the experimentally obtained bending and torsion results in a standard nonlinear least square procedure to determine the rigidities in the x and y directions and the Poisson’s ratios directly. Numerical simulation of the method indicates that the beam model overestimates the elastic modulii by 4 to 7 percent and the corresponding rigidities by 7 to 13 percent.

Strength of AAAS Composites with Ceramic Precursor over Time

2021 ◽  
Vol 322 ◽  
pp. 60-65
Author(s):  
Petr Frantík ◽  
Pavla Rovnaníková ◽  
Zbyněk Keršner
Keyword(s):  
Compressive Strength ◽  
Least Squares Method ◽  
Bending Tests ◽  
Three Point Bending ◽  
Dependent Change ◽  
Horizontal Asymptote ◽  
Ceramic Precursors ◽  
Time Dependent Change ◽  
Alkaline Activator ◽  
Alkali Activated

The paper deals with the approximation of the time evolution of the strengths of selected alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors. Composites made of brick dust as a precursor and an alkaline activator with a silicate modulus of Ms = 0.8, 1.0, 1.2, 1.4, and 1.6 were investigated. The filler consisted of standard quartz sand in one case, and crushed brick in the other. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were tested in three-point bending after 7, 28, 90, and 300 days of maturation. From each composite, 3 specimens were tested and the compressive strength was determined from the 6 specimen parts that remained after the bending tests. The obtained flexural and compressive strength values for the abovementioned 4 composite ages were approximated by the exponential function , where the coefficient a represents a horizontal asymptote to the approximation curve, i.e. the theoretical strength of the composite at time t = ∞; the exponential term of the approximation with the coefficients b and c expresses the degree of the time-dependent change of the respective compressive strength in the interval t = (0, ∞). The approximation was performed with the least squares method using genetic algorithms implemented in the Java GA package with open source code.

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