scholarly journals Verification of Brittle Fracture Criteria for Bimaterial Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 44-48
Author(s):  
Grzegorz Mieczkowski ◽  
Krzysztof Molski
Keyword(s):  
Experimental Data ◽  
Composite Materials ◽  
Cyclic Loading ◽  
Brittle Fracture ◽  
Axial Loading ◽  
Loading Conditions ◽  
Fracture Criteria ◽  
Interfacial Cracks ◽  
Theoretical Results ◽  
Brittle Fracture Criteria

Abstract The increasing application of composite materials in the construction of machines causes strong need for modelling and evaluating their strength. There are many well known hypotheses used for homogeneous materials subjected to monotone and cyclic loading conditions, which have been verified experimentally by various authors. These hypotheses should be verified also for composite materials. This paper provides experimental and theoretical results of such verifications for bimaterial structures with interfacial cracks. Three well known fracture hypotheses of: Griffith, McClintock and Novozhilov were chosen. The theoretical critical load values arising from each hypotheses were compared with the experimental data including uni and multi-axial loading conditions. All tests were carried out with using specially prepared specimens of steel and PMMA.

Fatigue Crack Growth Tests on Glass Fibre Reinforced Polymer Matrix Composite

2005 ◽  
Vol 473-474 ◽  
pp. 189-194
Author(s):  
Zilia Csomós ◽  
János Lukács
Keyword(s):  
Cyclic Loading ◽  
Crack Opening Displacement ◽  
Matrix Composite ◽  
Glass Fibre ◽  
Crack Opening ◽  
Loading Conditions ◽  
Opening Displacement ◽  
Interfacial Cracks ◽  
Glass Fibre Reinforced ◽  
Number Of Cycles

E-glass fibre reinforced polyester matrix composite was investigated, which was made by pullwinding process. Round three point bending (RTPB) specimens were tested under quasi-static and mode I cyclic loading conditions. Load vs. displacement (F-f), load vs. crack opening displacement (F-v) and crack opening displacement range vs. number of cycles (ΔCOD-N) curves were registered and analysed. Interfacial cracks were caused the final longitudinal fracture of the specimens under quasi-static and cyclic loading conditions.

Brittle Fracture Criteria Transferability Evaluation by Testing on Different Specimen Geometries

2008 ◽  
Author(s):  
S. Chapuliot ◽  
S. Marie
Keyword(s):  
Brittle Fracture ◽  
Critical Stress ◽  
Master Curve ◽  
Numerical Study ◽  
Fracture Criteria ◽  
Vessel Steel ◽  
Stress Criterion ◽  
Probability Of Fracture ◽  
Two Stages ◽  
Brittle Fracture Criteria

This paper describes an experimental and numerical study to assess the transposability of brittle fracture criteria from specimens of one type of geometry to another. The overall “master curve” approach, the Beremin model and a proposed model using the concept of critical stress were accordingly analysed. The experimental work supporting the analysis was made on 16MND5 reactor vessel steel. This was in the form of CT25 specimens, taken as the reference type, SENT specimens, ring specimens and CTpor specimens, which are CT specimens with a semi-elliptical surface defect. The analysis itself was made in two stages: the models were first calibrated on the basis of CT25 test results, then they were applied to specimens of other geometries. We then demonstrate that, in all cases, the models correctly replicated the variation of toughness (as measured on a CT25 specimen) with temperature. However, they all failed when applied to SENT and ring specimens, where calculation underestimates the probability of fracture. For CTpor specimens, the results are better, the master curve approach and the critical stress criterion give satisfactory results (but it has not yet been possible to apply the Beremin method). This paper concludes with a detailed analysis of the crack tip stress and strain fields, followed by an attempt to explain the differences between the different types of behaviour observed.

The Effective Thermal Conductivity of Composite Materials with Spherical Dispersed Phase

2011 ◽  
Vol 239-242 ◽  
pp. 1870-1874 ◽  
Author(s):  
Bin Wan ◽  
Kai Yue ◽  
Lian Cun Zheng ◽  
Xin Xin Zhang
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Composite Materials ◽  
Theoretical Result ◽  
Effective Thermal Conductivity ◽  
Integration Method ◽  
Dispersed Phase ◽  
Porous Composite ◽  
Resistance Model ◽  
Theoretical Results

The derivation of effective thermal conductivity (ETC) for composite materials is a long-standing thermal transport problem. Based on the thermal resistance model and integration method, two analytical solutions of the ETC of composite materials, in which the dispersed phase consists of spheres in cubic arrangements, were derived either neglecting or considering the effect of radiation. As the effect of radiation in porous composite materials is considered, the theoretical result indicates that the effect of radiation cannot be neglected as the temperature or porosity of composite materials is high. The differences between the theoretical results and experimental data of the ETC of porous composite materials are acceptable.

scholarly journals Моделирование динамического старта трещины на основе перидинамической численной модели и критерия инкубационного времени

2021 ◽  
Vol 91 (3) ◽  
pp. 435
Author(s):  
М.О. Игнатьев ◽  
Ю.В. Петров ◽  
Н.А. Казаринов
Keyword(s):  
Experimental Data ◽  
Brittle Fracture ◽  
Crack Initiation ◽  
Polymer Material ◽  
High Speed ◽  
Numerical Scheme ◽  
Glassy Polymer ◽  
Fracture Model ◽  
Loading Conditions ◽  
Dynamic Brittle Fracture

The problems of dynamic brittle fracture under the high-speed loading conditions were investigated. A new numerical scheme based on the peridynamic approach and a structural-time fracture model is used to predict the crack initiation in the specimens of glassy polymer material. Comparison of numerical results with experimental data is presented

The Influence of the Temperature Gradient near the Crack Surface on its Stability under Steady-State Thermomechanical Effects

2019 ◽  
Vol 974 ◽  
pp. 496-504
Author(s):  
V.V. Shevelev ◽  
L.M. Ozherelkova ◽  
I.R. Tishaeva
Keyword(s):  
Temperature Gradient ◽  
Brittle Fracture ◽  
Tensile Stress ◽  
Crack Surface ◽  
Circular Disk ◽  
Theory Of Elasticity ◽  
Uniaxial Tensile ◽  
Fracture Criteria ◽  
Uniaxial Tensile Stress ◽  
Brittle Fracture Criteria

The development of methods for predicting the reliability of structural elements based on brittle fracture criteria is a rather complex mathematical task. This is due to the fact that these criteria are usually obtained in the framework of the mathematical theory of cracks, the boundary problems of which allow a limited number of exact analytical solutions. To this we must add that the brittle fracture of materials with disc-shaped circular fractures has been studied in thermomechanics and in the kinetic theory of strength, from our point of view, is not enough and research in this area seems to be relevant to us. In this regard, in this work, within the framework of the linear theory of elasticity, two cases of external impact on a material containing a circular disk-shaped fracture are considered: mechanical, in the form of a uniaxial tensile stress, and temperature, in the form of a temperature gradient in the region of a material containing a circular disk-shaped crack destruction. From the extremum condition, brittle fracture criteria such as the Griffith criterion are obtained both for the case of only mechanical loading of the material with uniaxial tensile stress, and for the case of only temperature exposure of the material in the form of a local temperature gradient at the crack surface.

Sign in / Sign up

Export Citation Format

Share Document