Size Effect on Strength of Bi-Material Joints of Steel With Fiber-Polymer Composite

2008 ◽  
Author(s):  
Zdeneˇk P. Bazˇant ◽  
Jia-Liang Le ◽  
Ferhun C. Caner ◽  
Qiang Yu
Keyword(s):  
Fracture Mechanics ◽  
Size Effect ◽  
Experimental Studies ◽  
Strength Criterion ◽  
Energy Criterion ◽  
Composite Joints ◽  
Metal Composite ◽  
Singular Stress ◽  
Hybrid Joint ◽  
Large Size

Metal-composite joints between steel ribs and advanced fiber-polymer composites are an effective structural system for hybrid ship hulls. Similar joints are of interest for fuel-efficient aircraft. The current designs of such joints are generally based on the strength criterion, which ignores fracture mechanics. Aimed at an efficient and reliable design, this study investigates the size effect on the strength of these joints theoretically, numerically and experimentally. The analytical formulation of the size effect is asymptotically anchored at the large-size limit in linear elastic fracture mechanics (LEFM). The bi-material corner of the joint is shown to have a singular stress field with complex singularity. The strength of the joint is determined by the energy criterion for the macrocrack initiation at the corner, from which the large-size asymptote of the size effect law has been derived. A general approximate size effect law, spanning all sizes and various joint angles, is further derived via asymptotic matching. Numerical analysis with cohesive fracture model is used to design the experiments. Experimental studies involve the testing of geometrically similar hybrid joint specimens with the size ratio of 1 : 4 : 12. The analytical, numerical and experimental studies all indicate that the strength of bimaterial metal-composite joints is subjected to a strong size effect.

Residual Strength Prediction Based on Size Effect of Cracked Concrete Members

2021 ◽  
pp. 1-24
Author(s):  
Ragip Ince ◽  
Cenk Fenerli
Keyword(s):  
Fracture Mechanics ◽  
Size Effect ◽  
Residual Strength ◽  
Experimental Studies ◽  
Test Results ◽  
Structural Members ◽  
Cracked Concrete ◽  
Concrete Members ◽  
Peak Loads ◽  
Nominal Strength

In engineering materials, defects, such as cracks, may occur during production and/or due to various reasons. One of the aims of fracture mechanics is to determine the fracture toughness-based residual strength of structural members with cracks. A quasi-brittle material, such as concrete or rock, may include certain defects, such as voids and cracks, even before being exposed to loads. Experimental analyses on concrete members indicated that specimens’ nominal strength values were decreased as their sizes increased while specimen geometry is the same. In fracture mechanics, this condition was defined as the “size effect” in both concrete and reinforced concrete units. In the literature, numerous theoretical and experimental studies were conducted on beams while compact split-tension specimens, particularly notched ones are limited. In this study, six series of notched beams with three different sizes and notched square prismatic specimens with four different sizes were tested. According to the test results, the peak loads were analyzed by using the fundamental theorem of the modified size effect law. In conclusion, two formulae were proposed to predict the flexural strength and the splitting strength of quasi-brittle bodies with cracks.

STRENGTH RESEARCH ON MULTI-ROW METAL-COMPOSITE JOINTS

2013 ◽  
Vol 44 (4) ◽  
pp. 559-573
Author(s):  
Yanina Stefanovna Borovskaya ◽  
Vyacheslav Ivanovich Grishin ◽  
Irakliy Nugzarovich Kacharava ◽  
Sergey Mikhaylovich Naumov
Keyword(s):  
Composite Joints ◽  
Metal Composite

scholarly journals Hydride-based antiperovskites with soft anionic sublattices as fast alkali ionic conductors

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shenghan Gao ◽  
Thibault Broux ◽  
Susumu Fujii ◽  
Cédric Tassel ◽  
Kentaro Yamamoto ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Ionic Conductivities ◽  
Cubic Phase ◽  
Ionic Conductors ◽  
Large Size ◽  
Migration Barriers ◽  
Soft Phonon Mode ◽  
Aliovalent Substitution ◽  
Cubic Forms ◽  
The Ideal

AbstractMost solid-state materials are composed of p-block anions, only in recent years the introduction of hydride anions (1s2) in oxides (e.g., SrVO2H, BaTi(O,H)3) has allowed the discovery of various interesting properties. Here we exploit the large polarizability of hydride anions (H–) together with chalcogenide (Ch2–) anions to construct a family of antiperovskites with soft anionic sublattices. The M3HCh antiperovskites (M = Li, Na) adopt the ideal cubic structure except orthorhombic Na3HS, despite the large variation in sizes of M and Ch. This unconventional robustness of cubic phase mainly originates from the large size-flexibility of the H– anion. Theoretical and experimental studies reveal low migration barriers for Li+/Na+ transport and high ionic conductivity, possibly promoted by a soft phonon mode associated with the rotational motion of HM6 octahedra in their cubic forms. Aliovalent substitution to create vacancies has further enhanced ionic conductivities of this series of antiperovskites, resulting in Na2.9H(Se0.9I0.1) achieving a high conductivity of ~1 × 10–4 S/cm (100 °C).

scholarly journals Feature Size Effect on Formability of Multilayer Metal Composite Sheets under Microscale Laser Flexible Forming

Metals ◽  
2017 ◽  
Vol 7 (7) ◽  
pp. 275 ◽  
Author(s):  
Huixia Liu ◽  
Wenhao Zhang ◽  
Jenn-Terng Gau ◽  
Zongbao Shen ◽  
Youjuan Ma ◽  
...  
Keyword(s):  
Size Effect ◽  
Metal Composite ◽  
Feature Size ◽  
Flexible Forming ◽  
Multilayer Metal

Fracture Mechanics of Thin Plates and Shells Under Combined Membrane, Bending, and Twisting Loads

2005 ◽  
Vol 58 (1) ◽  
pp. 37-48 ◽  
Author(s):  
Alan T. Zehnder ◽  
Mark J. Viz
Keyword(s):  
Fracture Mechanics ◽  
Plate Theory ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Crack Tip ◽  
Thin Plates ◽  
Element Analysis ◽  
Crack Tip Fields ◽  
Plates And Shells ◽  
Membrane Bending

The fracture mechanics of plates and shells under membrane, bending, twisting, and shearing loads are reviewed, starting with the crack tip fields for plane stress, Kirchhoff, and Reissner theories. The energy release rate for each of these theories is calculated and is used to determine the relation between the Kirchhoff and Reissner theories for thin plates. For thicker plates, this relationship is explored using three-dimensional finite element analysis. The validity of the application of two-dimensional (plate theory) solutions to actual three-dimensional objects is analyzed and discussed. Crack tip fields in plates undergoing large deflection are analyzed using von Ka´rma´n theory. Solutions for cracked shells are discussed as well. A number of computational methods for determining stress intensity factors in plates and shells are discussed. Applications of these computational approaches to aircraft structures are examined. The relatively few experimental studies of fracture in plates under bending and twisting loads are also reviewed. There are 101 references cited in this article.

Fracture Mechanics in Pavement Engineering: The Specimen-Size Effect

1997 ◽  
Vol 1568 (1) ◽  
pp. 10-16 ◽  
Author(s):  
Anastasios M. Ioannides
Keyword(s):  
Fracture Mechanics ◽  
Size Effect ◽  
Specimen Size ◽  
Pavement Design ◽  
Crack Model ◽  
Design Procedures ◽  
Engineering Discipline ◽  
Pavement Engineering ◽  
Slow Progress ◽  
Mechanics Concepts

Application of fracture mechanics concepts developed in various branches of engineering to the pavement problem can address current limitations, thereby advancing considerably existing pavement design procedures. The state of the art in fracture mechanics applications to pavement engineering is summarized, and an in-depth discussion of one of the major concerns in such applications, the specimen-size effect, is provided. It is concluded that the fictitious crack model proposed by Hillerborg appears most promising for computerized application to pavements. The similitude concepts developed by Bache will be very useful in such efforts. Both the desirability and the scarcity of suitable candidates to replace Miner’s cumulative linear fatigue hypothesis in conventional pavement design are confirmed. Fracture mechanics is shown to be a very promising engineering discipline from which innovations could be transplanted to pavement activities. Nonetheless, it is pointed out that rather slow progress characterizes fracture mechanics developments in general. Pavement engineers clearly need to remain abreast of and involved in fracture mechanics activities.

Wedge-Splitting Test – Determination of Minimal Starting Notch Length for Various Cement Based Composites Part I: Cohesive Crack Modelling

2010 ◽  
Vol 452-453 ◽  
pp. 77-80 ◽  
Author(s):  
Václav Veselý ◽  
Ladislav Řoutil ◽  
Stanislav Seitl
Keyword(s):  
Fracture Mechanics ◽  
Cohesive Crack ◽  
Crack Model ◽  
Singular Stress ◽  
Initiation Point ◽  
Linear Elastic ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Notch Length ◽  
Wedge Splitting

The geometric proportions of cube-shaped specimens subjected to wedge-splitting tests are numerically studied in the paper. The minimal notch length for specimens made of cement based composites varying in characteristic length of the material (a measure of material brittle-ness/heterogeneity) is verified using finite element method code with an implemented cohesive crack model (ATENA). The problem of assigning the crack initiation point (the notch tip vs. the groove corner in the load-imposing area of the specimen) is solved numerically also using both the theory of linear elastic fracture mechanics and the theory of the fracture mechanics of generalized singular stress concentrators in the second part of the two-part paper. Results ob-tained by the different approaches are compared. The minimal notch length is recommended.

Sign in / Sign up

Export Citation Format

Share Document