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Showing 1 to 20 of 161 for “"Mode I"”.
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Experimentation of Mode I and Mode II Fracture of Uni-Directional Composites and Finite Element Analysis of Mode I Fracture Using Cohesive Contact
… One of the most prevalent and limiting mode of failure within composite laminates is delamination, since it not only reduces a structures stiffness and strength, but can be very difficult to detect without the use of special non-destructive equipment. Industry testing organizations have …
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Mode I Fracture Testing on Zirconium Foils Under Plane-stress Condition
… with Zr foils. Combined with finite element modeling, scanning electron microscopy analysis, and digital image correlation analysis, the fracture behavior at a crack tip from both macroscopic strain analysis and microscopic dislocation motion analysis was achieved. The current study is …
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Mode I Delamination Fracture Characterization of Polymeric Composites under Elevated Temperature
<p>Delamination is one of the major failure modes seen in the laminated polymeric matrix composite (PMC). Accurate prediction of delamination initiation and propagation is important for the design and analysis of robust composite structures. Existing experimental methodologies that are based on …
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Mode I Fracture Toughness Testing of Friction Stir Processed HSLA-65
… stir welding for use in Naval construction, mode one elastic-plastic fracture toughness of friction stir processed HSLA-65 was determined using current ASTM 1820 and BS 7448 standards. Double-sided welds were used to achieve 12.7 mm thick samples. A constant feed rate of 100 mm/min was used …
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Durability and mode-I fracture of fiber-reinforced plastic (FRP)/wood interface bond
… developed, and this specimen is used to evaluate Mode-I fracture of interface bonds; interface fracture toughness data are experimentally obtained for dry, wet and 3-cycle aging conditions. (Abstract shortened by UMI.).
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Mode I and Mode II Measurements For Stiction Failed Micro-Electro-Mechanical Systems
… have constructed an apparatus to determine the Mode I, II, and III interfacial adhesion energies of MEMS devices failed on a substrate. Though our method is general, we are specifically focused on devices created using the SUMMiT V process. An apparatus has been constructed that has 8 …
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Fracture Characteristics of Asphalt Concrete in Mode I, Mode II, and Mixed-Mode
… above were used to develop and validate a new Mode II test for asphalt concrete. No previous literature was found that attempted to capture Mode II fracture energy in asphalt concrete, so a test was developed from an extensive review of Mode II tests in the fields of metal, plastic, and PCC. …
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Fracture toughness determination and micromechanics of rock under Mode I and Mode II loading
… new experimental method for the determination of Mode II (shear) fracture toughness, KIIC of rock and compares the outcome to results from Mode I (tensile) fracture toughness, KIC, testing using the International Society of Rock Mechanics Chevron-Bend method.Critical Mode I fracture growth at …
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Multi-paradigm modeling of mode I&II dynamic fracture mechanisms in single crystal silicon
… silicon fracture, but are unreliable and most models could not be validated against experimental results. Here we propose to use MD modeling based on a novel first principles reactive force fields ReaxFF, which has shown to be an accurate model to describe fracture processes of silicon. Two …
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Synthesis, characterization, and mode I fracture toughness of aligned carbon nanotube polymer matrix nanocomposites
… composites, particularly steady state Mode I fracture toughness, RTM6 and EPON 862/W epoxy based vertically-aligned carbon nanotube (A-CNT) polymer nanocomposites (A-PNCs) are manufactured. These A-PNCs can be tested to isolate structure-property relationships between the polymer matrix …
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A Mesh Objective Algorithm for Modeling Mode-I Cracks Using a Standard Finite Element Formulation
… efficient mesh objective algorithm for modeling mode-I cracks is developed and implemented within a standard finite element formulation. The algorithm applies the crack opening displacements across the standard nodal degrees of freedom that is consistent with formalism of the …
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Effects of Voids on Delamination Behavior Under Static and Fatigue Mode I and Mode II
… or interlaminar failure is a serious failure mode observed in composite structures. Even partial delamination will lead to a loss of local stiffness, which can preclude buckling failure. Manufacturing process defects such as voids and fiber waviness degrade the fatigue life and delamination …
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Mechanical enhancement of woven composites with radially aligned carbon nanotubes (CNTs) : investigation of Mode I fracture toughness
… increased complexity and challenging failure modes. Matrix-rich regions at ply interfaces especially are susceptible to damage and matrix cracking, leading to delamination and a reduction of mechanical properties. Several manufacturing solutions such as stitching, z-pinning, and braiding have …
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Experimental Characterization of Mode I Fracture Toughness of Reinforced Carbon Fiber Laminate with Nano-Cellulose and CNT Additives
Effective treatment of carbon fiber components to improve delamination resistance is vital to the application of such materials since delamination is one of the biggest concerns regarding the use of composites in the aerospace sector. Due to the significant application benefit gained from increased …
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Mode-I Fracture in Bonded Wood: Studies of Adhesive Thermal Stability, and of the Effects of Wood Surface Deactivation
… studies; the common theme in each was the use of mode-I fracture testing to evaluate wood adhesion. In the first study, mode-I fracture testing was used to compare the thermal stability of polyurethane (PUR) and resorcinol-formaldehyde (RF) wood adhesives. Bonded specimens for both adhesives were …
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Response and Failure of Adhesively Bonded Automotive Composite Structures under Impact Loads
… Based on the use of a modified drop tower, mode I, II, and mixed mode values for critical energy release rate were determined for a composite/epoxy system and used to create a fracture failure envelope. Because load measurements become erratic and unreliable at higher test rates, …
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Dynamic Mixed-Mode Fracture of Bonded Composite Joints for Automotive Crashworthiness
An experimental evaluation of the mixed-mode fracture behavior of bonded composite joints is presented. Commonly used experimental techniques for characterizing the mode I, mixed-mode I/II, mode II, and mode III fracture behavior have been employed for the purpose of developing a fracture envelope …
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Fracture mechanics and its application in rock excavation
… two chevron notched specimen geometries for rock Mode I fracture toughness measurement, CB and SR, recommended by the ISRM have several disadvantages, such as very low loads required to initiate failure, complicated loading fixtures, difficult to be developed for rock mixed mode fracture testing, …
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Face Sheet/core Debonding In Sandwich Composites Under Static And Fatigue Loading
… interface under static and fatigue for mode I and mixed mode loading. For mode I static loading two types of delamination experiments, namely T-peel test and wedge test were implemented to evaluate fracture toughness in polyurethane foam core sandwich composites. It is shown that both …
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