Predicting fracture patterns in simulations of brittle materials under variable load and material strength

2017 ◽  
Author(s):  
Miroslav Stoyanov ◽  
Pablo Seleson ◽  
Clayton Webster
Keyword(s):  
Brittle Materials ◽  
Material Strength ◽  
Variable Load ◽  
Fracture Patterns

Relation Between Stochastic Failure Location and Strength in Brittle Materials

2005 ◽  
Vol 73 (4) ◽  
pp. 698-701 ◽  
Author(s):  
Sefi Givli ◽  
Eli Altus
Keyword(s):  
Stress Field ◽  
Brittle Materials ◽  
Simple Function ◽  
Statistical Characteristics ◽  
Material Strength ◽  
One Dimensional ◽  
Specific Strength ◽  
Weakest Link ◽  
Average Variance ◽  
Failure Location

Statistical characteristics of failure location and their relation to strength in brittle materials are studied. One-dimensional rod and bending of a beam under arbitrary distributed loads are studied as examples. The analysis is based on the weakest link approach, and is not confined to specific strength distributions (such as Weibull, Gaussian, etc.). It is found that the statistical moments of the failure location (average, variance, etc.) are directly related to the area moments (centroid, inertia, etc.) of a simple function of the stress field. Therefore, important information related to material strength can be experimentally obtained based on measuring failure locations. Such experiments do not require the measurement of stresses, strains, or displacements, and are very attractive for MEMS/NEMS applications. The approach is general and can be applied to other types of testing specimens.

scholarly journals Forensic Fractography of Bone

2021 ◽  
Author(s):  
Angi Christensen ◽  
John Rickman ◽  
Hugh Berryman
Keyword(s):  
Fracture Mechanics ◽  
Forensic Anthropology ◽  
Brittle Materials ◽  
Material Failure ◽  
Skeletal Trauma ◽  
Cracking Behavior ◽  
Fracture Patterns ◽  
Cause Of Failure ◽  
Physical Laws ◽  
Scientific Fields

Fractography involves the study of fractures and cracks in a material in order to understand the cause of failure. Even as a complex, highly hierarchical composite, bone is a material that obeys physical laws, including cracking behavior. The fields of fractography and fracture mechanics, therefore, have much to offer in our understanding of bone’s response to loading and force. Here we discuss how fractography can be used in the assessment of fractures originating from impacts including those from projectiles. Fractures and fracture patterns frequently associated with impact trauma—including radial fractures, circumferential fractures, and beveling—are described and used interpretively in forensic analyses; however, the mechanisms for their production and arrangement are often underutilized in fully understanding the trauma event. These mechanisms are reviewed here from a fractography perspective. Furthermore, a review is presented of new data indicating that beveling in bone associated with impacts, especially with projectiles, is produced by cone cracking, a process that is also well documented in other brittle materials. This information can be used to enhance understanding of impact trauma in general, as well as in the context of specific forensic cases. Moreover, describing and interpreting skeletal trauma within the context of fracture mechanics and fractography has the advantage of aligning the nomenclature used in forensic anthropology with that used in other scientific fields, particularly those involved in the study of material failure. To facilitate this alignment, we provide discussion and definitions for various fractography-related terms.

scholarly journals Modeling and Design of SHPB to Characterize Brittle Materials under Compression for High Strain Rates

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2191 ◽  
Author(s):  
Tomasz Jankowiak ◽  
Alexis Rusinek ◽  
George Z. Voyiadjis
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Brittle Materials ◽  
Material Strength ◽  
Strain Rates ◽  
Analytical Prediction ◽  
Hopkinson Pressure Bar ◽  
Finite Element Software ◽  
Pressure Bar

This paper presents an analytical prediction coupled with numerical simulations of a split Hopkinson pressure bar (SHPB) that could be used during further experiments to measure the dynamic compression strength of concrete. The current study combines experimental, modeling and numerical results, permitting an inverse method by which to validate measurements. An analytical prediction is conducted to determine the waves propagation present in SHPB using a one-dimensional theory and assuming a strain rate dependence of the material strength. This method can be used by designers of new SPHB experimental setups to predict compressive strength or strain rates reached during tests, or to check the consistencies of predicted results. Numerical simulation results obtained using LS-DYNA finite element software are also presented in this paper, and are used to compare the predictions with the analytical results. This work focuses on an SPHB setup that can accurately identify the strain rate sensitivities of concrete or brittle materials.

Mesoscale Models Characterizing Material Property Fields Used As a Basis for Predicting Fracture Patterns in Quasi-Brittle Materials

2017 ◽  
Author(s):  
Katherine A. Acton ◽  
Sarah C. Baxter ◽  
Bahador Bahmani ◽  
Philip L. Clarke ◽  
Reza Abedi
Keyword(s):  
Crack Propagation ◽  
Material Property ◽  
Mesoscale Model ◽  
Voronoi Tessellation ◽  
Brittle Materials ◽  
Material Behavior ◽  
Small Scale ◽  
Element Analysis ◽  
Stress Criterion ◽  
Fracture Patterns

To accurately predict fracture patterns in quasi-brittle materials, it is necessary to accurately characterize heterogeneity in the properties of a material microstructure. This heterogeneity influences crack propagation at weaker points. Also, inherent randomness in localized material properties creates variability in crack propagation in a population of nominally identical material samples. In order to account for heterogeneity in the strength properties of a material at a small scale (or “microscale”), a mesoscale model is developed at an intermediate scale, smaller than the size of the overall structure. A central challenge of characterizing material behavior at a scale below the representative volume element (RVE), is that the stress/strain relationship is dependent upon boundary conditions imposed. To mitigate error associated with boundary condition effects, statistical volume elements (SVE) are characterized using a Voronoi tessellation based partitioning method. A moving window approach is used in which partitioned Voronoi SVE are analysed using finite element analysis (FEA) to determine a limiting stress criterion for each window. Results are obtained for hydrostatic, pure and simple shear uniform strain conditions. A method is developed to use superposition of results obtained to approximate SVE behavior under other loading conditions. These results are used to determine a set of strength parameters for mesoscale material property fields. These random fields are then used as a basis for input in to a fracture model to predict fracture patterns in quasi-brittle materials.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

Failure wave as resonance excitation of collective burst modes of defects in shocked brittle materials

2000 ◽  
Vol 10 (PR9) ◽  
pp. Pr9-811-Pr9-816 ◽  
Author(s):  
O. A. Plekhov ◽  
D. N. Eremeev ◽  
O. B. Naimark
Keyword(s):  
Brittle Materials ◽  
Resonance Excitation ◽  
Failure Wave

Analisis Daya Dukung Tanah Dan Bahan Pondasi Tiang Pancang Pada Pembangunan Jembatan Kab. Jombang

2020 ◽  
Vol 9 (1) ◽  
pp. 32-37
Author(s):  
Ruslan Hidayat ◽  
Saiful Arfaah
Keyword(s):  
Carrying Capacity ◽  
Pile Foundation ◽  
Heavy Traffic ◽  
Traffic Volume ◽  
Material Strength ◽  
Cone Penetrometer ◽  
The Village

One of the most important factors in the structure of the pile foundation in the construction of the bridge is the carrying capacity of the soil so as not to collapse. Construction of a bridge in the village of Klitik in Jombang Regency to be built due to heavy traffic volume. The foundation plan to be used is a pile foundation with a diameter of 50 cm, the problem is what is the value of carrying capacity of soil and material. The equipment used is the Dutch Cone Penetrometer with a capacity of 2.50 tons with an Adhesion Jacket Cone. The detailed specifications of this sondir are as follows: Area conus 10 cm², piston area 10 cm², coat area 100 cm², as for the results obtained The carrying capacity of the soil is 60.00 tons for a diameter of 30 cm, 81,667 tons for a diameter of 35 cm, 106,667 tons for a diameter of 40 cm, 150,000 tons for a diameter of 50 cm for material strength of 54,00 tons for a diameter of 30 cm, 73,500 tons for a diameter of 35 cm, 96,00 tons for a diameter of 40 cm, 166,666 tons for a diameter of 50 cm

Acute Traumatic Cervical Facet Fractures

2018 ◽  
Vol 1 (2) ◽  
pp. 5
Author(s):  
Shankar Gopinat
Keyword(s):  
Spinal Cord ◽  
Cervical Spine ◽  
Early Surgery ◽  
Initial Assessment ◽  
Trauma Patients ◽  
Spinal Stability ◽  
Fracture Patterns ◽  
Spine Ct ◽  
Cervical Facet

Acute cervical facet fractures are increasingly being detected due to the use of cervical spine CT imaging in the initial assessment of trauma patients. For displaced cervical facet fractures with dislocations and subluxations, early surgery can decompress the spinal cord and stabilize the spine. For patients with non-displaced cervical facet fractures, the challenge in managing these patients is the determination of spinal stability. Although many of the patients with non-displaced cervical facet fractures can be managed with a cervical collar, the imaging needs to be analyzed carefully since certain fracture patterns may be better managed with early surgical stabilization.

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