Characterization of the Loading Rate Dependent Fracture Behavior over a Wide Loading Rate Range Using Charpy Specimens

2014 ◽  
Vol 566 ◽  
pp. 286-291
Author(s):  
Zoltan Major ◽  
Martin Reiter
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Loading Rate ◽  
Polymeric Materials ◽  
Bending Test ◽  
Rate Range ◽  
Rate Dependent ◽  
Engineering Polymers ◽  
Dynamic Key

The fracture behavior of engineering polymers is usually characterized at high loading rates using Charpy specimens. However, due to the presence of dynamic effects the conventional force based analysis for determining fracture toughness values is applicable only up to 1 m/s using tree point bending test configurations. This difficulty can be overcome in principle, by applying dynamic analysis methods (e.g. dynamic key curve (DKC) analysis) or by applying tensile loading fracture configurations. The applicability of pre-cracked Charpy specimens for determining fracture toughness values for polymeric materials over a wide loading rate range is investigated in this study.

Loading rate effect on fracture behavior of fiber reinforced high strength concrete using a semi-circular bending test

2020 ◽  
Vol 240 ◽  
pp. 117681
Author(s):  
Mehran Aziminezhad ◽  
Sahand Mardi ◽  
Pouria Hajikarimi ◽  
Fereidoon Moghadas Nejad ◽  
Amir H. Gandomi
Keyword(s):  
High Strength Concrete ◽  
Fracture Behavior ◽  
Loading Rate ◽  
High Strength ◽  
Rate Effect ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Strength Concrete

Mechanical Property and Oxidation Behavior of LPS-SiC Materials

2006 ◽  
Vol 321-323 ◽  
pp. 913-916
Author(s):  
Sang Ll Lee ◽  
Yun Seok Shin ◽  
Jin Kyung Lee ◽  
Jong Baek Lee ◽  
Jun Young Park
Keyword(s):  
Mechanical Property ◽  
Fracture Toughness ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Indentation Test ◽  
Bending Test ◽  
Secondary Phases ◽  
Three Point Bending ◽  
Different Temperatures

The microstructure and the mechanical property of liquid phase sintered (LPS) SiC materials with oxide secondary phases have been investigated. The strength variation of LPS-SiC materials exposed at the elevated temperatures has been also examined. LPS-SiC materials were sintered at the different temperatures using two types of Al2O3/Y2O3 compositional ratio. The characterization of LPS-SiC materials was investigated by means of SEM with EDS, three point bending test and indentation test. The LPS-SiC material with a density of about 3.2 Mg/m3 represented a flexural strength of about 800 MPa and a fracture toughness of about 9.0 MPa⋅√m.

scholarly journals FDEM Modelling of Rock Fracture Process during Three-Point Bending Test under Quasistatic and Dynamic Loading Conditions

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Huaming An ◽  
Yushan Song ◽  
Hongyuan Liu
Keyword(s):  
Fracture Toughness ◽  
Dynamic Loading ◽  
Fracture Process ◽  
Loading Rate ◽  
Rock Fracture ◽  
Mesh Size ◽  
Bending Test ◽  
Loading Conditions ◽  
Three Point Bending ◽  
Dynamic Loading Conditions

A hybrid finite-discrete element method (FDEM) is proposed to model rock fracture initiation and propagation during a three-point bending test under quasistatic and dynamic loading conditions. Three fracture models have been implemented in the FDEM to model the transition from continuum to discontinuum through fracture and fragmentation. The loading rate effect on rock behaviour has been taken into account by the implementation of the relationship between the static and dynamic rock strengths derived from dynamic rock fracture experiments. The Brazilian tensile strength test has been modelled to calibrate the FDEM. The FDEM can well model the stress and fracture propagation and well show the stress distribution along the vertical diameter of the disc during the Brazilian tensile strength test. Then, FDEM is implemented to study the rock fracture process during three-point bending tests under quasistatic and dynamic loading conditions. The FDEM has well modelled the stress and fracture propagation and can obtain reasonable fracture toughness. After that, the effects of the loading rate on the rock strength and rock fracture toughness are discussed, and the mesh size and mesh orientation on the fracture patterns are also discussed. It is concluded that the FDEM can well model the rock fracture process by the implementation of the three fracture models. The FDEM can capture the loading rate effect on rock strength and rock fracture toughness. The FDEM is a valuable tool for studying the rock behaviour on the dynamic loading although the proposed method is sensitive to the mesh size and mesh orientation.

FRACTURE BEHAVIOR OF Zr-BASED BULK METALLIC GLASS UNDER IMPACT LOADING

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4359-4364 ◽  
Author(s):  
HYUNG-SEOP SHIN ◽  
KI-HYUN KIM ◽  
SANG-YEOB OH
Keyword(s):  
Fracture Toughness ◽  
Crack Initiation ◽  
Fracture Energy ◽  
Impact Loading ◽  
Static Loading ◽  
Fracture Behavior ◽  
Loading Rate ◽  
Shear Bands ◽  
Maximum Load ◽  
Cu Alloy

The fracture behavior of a Zr -based bulk amorphous metal under impact loading using subsize V-shaped Charpy specimens was investigated. Influences of loading rate on the fracture behavior of amorphous Zr - Al - Ni - Cu alloy were examined. As a result, the maximum load and absorbed fracture energy under impact loading were lower than those under quasi-static loading. A large part of the absorbed fracture energy in the Zr -based BMG was consumed in the process for crack initiation and not for crack propagation. In addition, fractographic characteristics of BMGs, especially the initiation and development of shear bands at the notch tip were investigated. Fractured surfaces under impact loading are smoother than those under quasi-static loading. The absorbed fracture energy appeared differently depending on the appearance of the shear bands developed. It can be found that the fracture energy and fracture toughness of Zr -based BMG are closely related with the extent of shear bands developed during fracture.

Fracture Toughness Characterization of Carbon Bonded Alumina Using Chevron Notched Specimens

2017 ◽  
Vol 754 ◽  
pp. 71-74 ◽  
Author(s):  
H. Zielke ◽  
Martin Abendroth ◽  
Meinhard Kuna
Keyword(s):  
Fracture Toughness ◽  
Ceramic Material ◽  
Bending Test ◽  
Parameter Study ◽  
Zone Model ◽  
Displacement Curve ◽  
Notched Specimens ◽  
Load Displacement ◽  
Set Up

A new generation of multifunctional filters is made of carbon bonded alumina and is investigated within the collaborative research center 920 (CRC920). These filters are used during a casting process with the aim of reducing non-metallic inclusions in the cast product. The high thermal and mechanical loading of the filter requires a fracture mechanical characterization of the investigated ceramic material. In order to determine the fracture toughness of the ceramic material, a chevron-notched beam method (CNB) is applied. A 4-point-bending test set-up was constructed and brought into service, at which the load-displacement curve of small chevron-notched specimens (5 x 6 x 25 mm3) can be measured. The set-up offers the possibility of testing specimens at temperatures up to 1000oC. Preceding numerically work using the finite element method was performed to identify a suitable notch geometry. For this purpose a cohesive zone model was used. A parameter study is presented, which shows the influence of the notch parameter on the load-displacement curve.

Determination of Fracture Toughness by Single and Double Action Tensile Impact Fracture Tests

2016 ◽  
Vol 715 ◽  
pp. 101-106
Author(s):  
Zoltan Major ◽  
Matei Miron ◽  
Imre Kallai
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Loading Rate ◽  
Testing Machine ◽  
Peak Load ◽  
High Rate ◽  
Test Set ◽  
Data Scatter ◽  
Fracture Tests ◽  
Set Up

The characterization of the loading rate dependence of the fracture behavior of polymers is of prime theoretical and practical interest for supporting demanding engineering applications. To gain more insight into the high rate fracture behavior of polymers, fracture tests were performed under tensile loading conditions up to 12 m/s loading rate using a neat model polymer (PVC grey) in this study. A conventional single actuator test set-up for compact tension C(T) specimens was developed based on the previous experience of the authors and implemented on a new high rate servohydraulic testing machine. In addition, a novel double action test set-up was developed by applying two twin actuators and implemented in a rigid horizontal test frame. The conventional load and force measurement was extended by instrumented test specimens and by a high speed optical strain analysis system for both set-ups. Force based fracture toughness values using the peak load values, KIcPL and displacement based values using the critical crack opening displacement (CTOD) KICCTOD were determined up to a loading rate of 10 m/s. While the KIcPL values decreased up to a loading rate 103 MPam1/2s-1 an increase with a high data scatter was observed above them. Corresponding to the CTOD values the calculated KICCTOD values revealed a slight decrease and moderate data scatter up to the maximal loading rate.

J-R Fracture Toughness of Nuclear Piping Materials Under Excessive Seismic Loading Condition

2016 ◽  
Author(s):  
Jin Weon Kim ◽  
Myung Rak Choi ◽  
Sang Bong Lee ◽  
Yun Jae Kim
Keyword(s):  
Fracture Toughness ◽  
Cyclic Loading ◽  
Fracture Resistance ◽  
Cyclic Load ◽  
Fracture Behavior ◽  
Loading Rate ◽  
Seismic Loading ◽  
Monotonic Loading ◽  
Rate Effect ◽  
Loading Conditions

This study investigated the loading rate effect on the fracture resistance under cyclic loading conditions to clearly understand the fracture behavior of piping materials under excessive seismic conditions. J-R fracture toughness tests were conducted under monotonic and cyclic loading conditions at various displacement rates at room temperature (RT) and the operating temperature of nuclear power plants (NPPs), i.e., 316°C. SA508 Gr. 1a lo w-alloy steel (LAS) and SA312 TP316 stainless steel (SS) piping materials were used for the tests. The fracture resistance under a reversible cyclic load was considerably lower than that under monotonic load regardless of test temperature, material, and loading rate. Under both cyclic and monotonic loading conditions, the fracture behavior of SA312 TP316 SS was independent of the loading rate at both RT and 316°C. For SA508 Gr. 1a LAS, the loading rate effect on the fracture behavior was appreciable at 316°C under both cyclic and monotonic loading conditions. However, the loading rate effect diminished when the cyclic load ratio (R) was −1. Thus, it was recognized that the fracture behavior of piping materials, including seismic loading characteristics, can be evaluated when tested under a cyclic load of R = −1 at a quasi-static loading rate.

Characterization of polymeric materials by TEM

1978 ◽  
Vol 36 (1) ◽  
pp. 488-489
Author(s):  
R.R. Russell
Keyword(s):  
Structural Characterization ◽  
Polymeric Materials ◽  
Transmission Electron ◽  
Polymer Microstructures ◽  
Characterization Studies ◽  
Engineering Polymers ◽  
Preparation Techniques ◽  
Application Engineer ◽  
Thin Samples

Structural characterization of the expanding cavalcade of engineering polymers is now as important to the materials application engineer as to the basic researcher. Direct transmission electron microscopy (TEM) is the primary method for delineation and evaluation of microstructures in many polymer blends and composites and thus plays a major role in characterization studies.Only TEM clearly resolves structural components, such as phases and fillers in many polymeric materials. This technique can also reveal the effects of strain (crazing, shearing or phase deformation) in polymer microstructures. Thus, by utilizing TEM, bulk structural documentation (Figure 1) as well as the results of laboratory testing (Figure 2) or manufacturing processes can be studied.Basic to successful direct TEM structural characterization of any material are reliable sample preparation techniques capable of producing thin samples which retain the true features of the bulk material.Ultramicrotomy is used extensively for producing such thin samples from polymers.

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