Effect of mixed mode fracture on ultimate strength of cracked tubular joints

by G. Yang

Publisher: UMIST in Manchester

Written in English
Published: Downloads: 909
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Edition Notes

StatementG. Yang ; supervised by F.M. Burdekin..
ContributionsBurdekin, F. M., Civil and Structural Engineering.
ID Numbers
Open LibraryOL16429302M

The author explains fracture mechanics and fatigue in terms the practicing engineer uses on a daily basis. For example, different material properties used in fracture mechanics are compared to Hook's Law, yield strength, and tensile strength, material properites common to structural engineers/5(7). A LOAD SHEDDING MODEL FOR FRACTURE MECHANICS ANALYSIS OF FATIGUE CRACKS IN TUBULAR JOINTS. The theoretical prediction of stress intensity factors for tubular welded joints is difficult due to the complex geometry. Therefore, in the past empirical equations based on experimental crack growth data have been developed.   Progress in the Analysis and Design of Marine Structures collects the contributions presented at MARSTRUCT , the 6 th International Conference on Marine Structures (Lisbon, Portugal, May ).. The MARSTRUCT series of Conferences started in Glasgow, UK in , the second event of the series having taken place in Lisbon, Portugal in March , the third in Cited by: 3. strength caused by a crack in this plate with a length 2a = 3 mm oriented normal to the tensile direction. Given: Young’s modulus E = GPa surface tension g e = 2 J/m 2 plastic energy per unit crack surface area g p = 2×10 4 J/m2 critical stress intensity factor K c = s c pa 5. Describe the effect of yield strength on fracture behaviour. Size: KB.

several fracture modes in polymer composites such as delamination or interlaminar fracture, matrix cracking or intralaminar fracture, matrix-fiber debonding, fiber breaking, fiber pullout etc [3]. In the fiber reinforced polymer composite, the matrix absorbs energy in tearing while the high strength fibers break by brittle cleavage [4].File Size: KB. Treatment of femoral neck fracture is defined based on the fracture pattern, bone quality, comorbidities and the physiological age of the patient. However, there is no doubt about the benefit of surgical treatment, which reduces the rate of morbidity and mortality. Such treatments are defined as joint replacement or fracture fixation.3Cited by: 3. Of particular concern is the effect on fracture toughness, with any effects of hydrogen being universally adverse. Data published by Graville et al (1) on the effect of hydrogen on notch tensile strength (assumed to be somewhat similar to effect on fracture toughness) in provide a useful summary of the generally observed effects. Wind turbine blades are subjected to complex multiaxial stress states during operation. A review of the literature suggests that mixed mode fracture toughness can be significantly less than that of the tensile opening mode (Mode I), implying that fracture failure can occur at a much lower load capacity if the structure is subject to mixed-mode loading.

Progress in the Analysis and Design of Marine Structures collects the contributions presented at MARSTRUCT , the 6th International Conference on Marine Structures (Lisbon, Portugal, May ). The MARSTRUCT series of Conferences started . Key statement: The present invention provides a random copolymer that is used for manufacturing a rubber having high fracture strength and excellent low loss properties (low heat generation properties) and that includes randomly arranged monomer units of a conjugated diene compound and of a non-conjugated olefin, a rubber composition containing the random copolymer, a crosslinked rubber. affect the fatigue strength by increasing the propensity for crack nucleation and its early growth causing the ultimate failure of the joint. From the literature review, it is understood that enormous research work has been carried out on fatigue and fracture behavior of Aluminum joints, but the reported literatures.   Although equations have been proposed to predict mixed-mode fracture toughness values based solely on measured values of G IC and G IIC, MMB testing is often performed at varying mode mixities and a curve fit of the data is used to arrive at a mixed-mode fracture criterion for delamination growth in composites.

Effect of mixed mode fracture on ultimate strength of cracked tubular joints by G. Yang Download PDF EPUB FB2

To quantify the effect of fracture failure on the ultimate strength of tubular joints, Qian and Zhang () have proposed an approach to integrate the material J-R curve in the limit load.

In this paper, the mixed-mode cohesive fracture behavior of adhesively bonded joints was investigated based on numerical analysis.

A modified version of Arcan specimen was employed to conduct a mixed-mode fracture test using a special loading device. A full range of mixed-mode loading conditions including pure mode-I and pure mode-II loading were created by ABAQUS : Reza Bakhtiari, Ehsan Darabi, Ali Ravaee.

In this paper, a procedure for the Mixed Mode fracture toughness characterization of adhesive joints will be described. A compact tension-shear (CTS) specimen geometry is adopted.

The procedure is applied to determine the Mixed Mode fracture toughness of bonded joints made of a commercial elastomer methacrilate by: When it comes to mixed-mode loading, the ratio of mode I and mode II in each case must be defined using a parameter.

For that purpose, the mixed-mode phase angle, ψ, is defined as: (1) ψ = tan-1 G II G I → ψ = 0 ° for pure mode I 0 ° Cited by: Modelling load transfer and mixed-mode fracture of ductile adhesive composite joints Article in International Journal of Adhesion and Adhesives 82 January with.

The value of the mixed-mode fracture toughness depends on the actual crack propagation mode and on the fracture parameter used. Ductile steel often displayed a decrease of fracture toughness with increasing mode II components [2]. In order to asses fracture toughness in a ductile cracked structure under mixed mode loading, the Tensile.

Fracture mechanics apparatus testing. For the Love of Physics - Walter Lewin - - Duration: Lectures by Walter Lewin. For the first time, a series of mixed mode I/II fracture experiments have been performed on both base material and three families of friction stir welds (FSWs) in mm thick, T aluminum plate; the FSW joints are designated hot, medium and cold due to the level of nominal weld energy input per unit weld length (specific weld energy) during the joining process.

Results from the. This paper examines mixed-Mode I-II-III fracture of adhesive joints using a new experimental method. The expressions used for the average energy release rate in Mode I, Mode II, and Mode III along the idealized straight crack front of a cracked, generalized adhesive sandwich are based on beam theory, the J-integral and a beam-on-elastic foundation by: 6.

The paper initially presents the results of a dynamic structural integrity assessment for fracture of cracked plate and tubular members under sinusoidal Effect of mixed mode fracture on ultimate strength of cracked tubular joints book at different frequencies.

The behavior of cracked members and joints in an offshore structure under wave loading (Stokes 5th order or gridded wave) is Cited by: 2. This book reviews recent research in the field of fatigue and fracture of adhesively-bonded composite joints.

The first part of the book discusses the experimental investigation of the reliability of adhesively-bonded composite joints, current research on understanding damage mechanisms, fatigue and fracture, durability and ageing as well as. Mixed-Mode Fracture Toughness Determination USING NON-CONVENTIONAL TECHNIQUES IDMEC- Pólo FEUP DEMec - FEUP ESM – Virginia Tech.

motivation the fracture characterization of bonded joints under mixed-mode loading is a mode III fracture modes for adhesive joints Figure 1.

Fracture modes. June 28th, Susceptibility to delamination is one of the major weaknesses of many advanced laminated composite structures. Knowledge of the interlaminar fracture resistance of composites is useful for product development and material selection.

Since delaminations can be subjected to and extended by loadings with a wide range of mode mixtures, it is important that the composite toughness be measured. Friction welding of wood is an assembly method that is still under investigation and development.

A possible application for welded wood joints is the fabrication of multi-layered panels (i.e., cross-laminated panels). In an effort to model the behavior of such products, work is needed to characterize the mechanical strength and fracture properties of welded joints produced with parallel and Cited by: 3.

Joints with deficient capacity are then sized again. At present, empirical expressions represent the state of the art for predicting the ultimate strength of tubular joints. They are based on axially loaded laboratory joint tests. Very little ultimate-strength data exist for bending or combined axial and bending by: 5.

MIXED MODE FRACTURE CHARACTERIZATION OF ADHESIVE JOINTS ij 0 W = ∫ ijd, (14) which has to be a potential to maintain the path independency of J.

Summarizing the assumptions the J-integral is only path independent, if the strain is small (see equation (12)) and W is independent of the load history.

Using the J-integral as a fracture criterion the. Mixed mode fracture in a certain high strength steel has been investigated through physical experiments and numerical calculations. The main objective has been to investigate the implications of local crack tip processes on the macroscopic mixed mode fracture behaviour.

A scrutiny of the fractured specimens revealed evidence of crack branching in all cases where β_eq Cited by: as a crack starter for the NPC tests.

The specimens were pre-cracked from this Teflon insert during the NPC fracture test to create a naturally occurring crack, from which to propagate the crack in the subsequent PC tests. Fracture testing was conducted on a total of 5 specimens from each manufacturer to determine GIIC.

The average mode II File Size: 1MB. This paper concerns on the development of numerical models for cracked square hollow sections (SHSs) T- Y- and K-joints. Based on these numerical models, the plastic collapse loads P c are calculated using nonlinear finite element method and through twice-elastic compliance criterion.

It is found that the numerical plastic collapse loads P c are slightly conservative compared with the ones Cited by: 7. The fracture toughness represents a material intrinsic parameter, it is actually known as the value of the produced critical stress intensity factor K c due to stress concentration at the crack tip zone when the crack is subjected to tensile stresses normal to the crack axis and the crack is called in that case mode-I crack (El-Sheikhy R.

& Al Cited by: 2. Mixed-mode fracture of concrete is encountered frequently in design of concrete structures. To accurately analyzed and design a concrete structure, it is essential to understand the failure mechanisms of concrete under mixed-mode types of loading.

A model, which was originally proposed for mode I failure of concrete, is extended to characterized mixed-mode crack by: M. Mirsayar / Engineering Solid Mechanics 2 () 71 Me T * 0 2 4 Case -1 Case -2 Case -3 Fig.

Variation of T* values versus Me in three cases A dimensionless parameter called the biaxiality ratio, B, has been introduced by Leevers and Radon () to normalize the T-stress relative to the stress intensity mixed mode loading.

Fatigue crack growth predictions based on fracture mechanics analysis are described. Validation of the fatigue prediction model has been made by comparison with stress intensity factor solutions in tubular connections and by comparison with observed crack growth in large scale test joints.

In the particular case of E1 =E2 =E, h1 =h2 =h, we obtain the following expressions: 2 3 12 2 2 EB h P a G s I = and 2 3 2 2 16 9 EB h P a G a II = where Pa = (P-R)/2 and Ps = (P+R)/2.

RESULTS AND DISCUSSIONS. Fig.3 gives the variation of critical strain energy release rate GTC = GI + GII of three composite adhesive joints as a function of the mixed mode ratio in term of GII/ Size: 77KB. FRACTURE OF CRACKED MEMBERS 1. The presence of a crack in a structure may weaken it so that it fails by fracturing in two or more t strength is limited by fracture, and when 0.

Failure Methodology of Mode-II Loaded Cracks As regards the specimen thickness requirement for determining valid fracture tough-nesses, the results indicate the usual behaviour when the mode-I fracture toughness KIc is considered: A practically constant value is.

The MMB test fixture is gaining popularity and is, today, the preferred method for quantifying the mixed-mode fracture toughness of composites, particularly now that ASTM D is available. The test specimen is simple and of a familiar form, and the test procedure is.

Strength, Fracture and Complexity: An International Journal is devoted to solving the problem of strength and fracture in a non-linear and systematic manner as a complexity system. It will welcome attempts to develop new paradigms and studies which fuse together nano, meso, microstructure, continuum and large-scale approaches.

The effect of LTN depth on the peak impact force, the crack initiation energy and Charpy fracture energy was investigated on a C70S6 carbon steel using an instrumented Charpy impact facility. It was reduced to a value Cited by: For example, the onset of fracture for a cracked body subjected to mixed-mode loading takes place according to the maximum tangential criterion when: (12) All specimens of all three groups were fatigue precracked to a/W = in a three point bend setup.

Full text of "Report of a workshop on requalification of tubular steel joints in offshore structures" See other formats NISTIR Report of a Workshop on Requalification of Tubular Steel Joints in Offshore Structures Building and Fire Research Laboratory National Institute of Standards and Technology Gaithersburg, Maryland QC )56 NO.

NIST United States Department of.WELDED JOINTS FRACTURE TOUGHNESS Fracture criterion for 19Mn5 steel pipes welded joints was taken J–integral and its critical value JIc, because defi-nition of this criterion less depends on the sizes of the specimen to be tested. Procedure of JIc calculation is de-scribed in the Anderson () and ASTM E ().Effect of mixing process on the fracture behavior of HA/PLLA Composites were investigated.

Fracture toughness values of HA/PLLA composites prepared under different mixing time and rotor speed were measured. The fracture surface morphology was also examined by scanning electron microscopy. It was found that the fracture toughness of HA/PLLA composite decreases due to decrease of ductile Cited by: 6.