The role of adhesive in the ballistic/structural performance of ceramic/polymer–matrix composite hybrid armor

Grujičić, M.; Pandurangan, B.; d’Entremont, Brian

doi:10.1016/j.matdes.2012.05.023

Cited by 94 publications

(28 citation statements)

References 20 publications

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“…(a) Diffusion rate of hydrogen along the grain-boundaries is quite small in comparison to its counterpart through the bulk, which is in complete agreement with the quantummechanical predictions; (b) Once a hydrogen atom has arrived at a grain-boundary, it becomes effectively trapped with very little mobility both in the directions along and normal to the grainboundary; (c) Mass transport of hydrogen from the crack-tip wake region along the adjoining grain-boundaries is effectively controlled not by the grain-boundary diffusion but rather by the diffusion of hydrogen through the adjoining bulk material and its deposition onto the advancing GB-hydrogen front (Ref [17][18][19][20]; (d) While the hydrogen diffusion from the crack-tip through the bulk to the advancing hydrogen-front is associated with a longer diffusion path, the effective hydrogen grain-boundary diffusivity is still controlled by its bulk component. This is the result of two effects: (i) substantially higher bulk diffusivity of hydrogen compared to its inter-granular counterpart; and (ii) the fact that the inter-granular and trans-granular diffusion paths are connected in parallel; and (e) Using the procedure described in Ref.…”

Section: Resultsmentioning

confidence: 99%

Wind-Turbine Gear-Box Roller-Bearing Premature-Failure Caused by Grain-Boundary Hydrogen Embrittlement: A Multi-physics Computational Investigation

Grujičić

Chenna

Galgalikar

et al. 2014

J. of Materi Eng and Perform

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To help overcome the problem of horizontal-axis wind-turbine (HAWT) gear-box roller-bearing prematurefailure, the root causes of this failure are currently being investigated using mainly laboratory and field-test experimental approaches. In the present work, an attempt is made to develop complementary computational methods and tools which can provide additional insight into the problem at hand (and do so with a substantially shorter turn-around time). Toward that end, a multi-physics computational framework has been developed which combines: (a) quantum-mechanical calculations of the grain-boundary hydrogenembrittlement phenomenon and hydrogen bulk/grain-boundary diffusion (the two phenomena currently believed to be the main contributors to the roller-bearing premature-failure); (b) atomic-scale kinetic Monte Carlo-based calculations of the hydrogen-induced embrittling effect ahead of the advancing crack-tip; and (c) a finite-element analysis of the damage progression in, and the final failure of a prototypical HAWT gear-box roller-bearing inner raceway. Within this approach, the key quantities which must be calculated using each computational methodology are identified, as well as the quantities which must be exchanged between different computational analyses. The work demonstrates that the application of the present multiphysics computational framework enables prediction of the expected life of the most failure-prone HAWT gear-box bearing elements.

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Section: Resultsmentioning

confidence: 99%

Wind-Turbine Gear-Box Roller-Bearing Premature-Failure Caused by Grain-Boundary Hydrogen Embrittlement: A Multi-physics Computational Investigation

Grujičić

Chenna

Galgalikar

et al. 2014

J. of Materi Eng and Perform

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“…Within this law, the maximum value of the shear stresses that can be transmitted (before the contacting surfaces begin to slide) is defined by a product of the contact pressure and a static (before sliding) and a kinetic (during sliding) friction coefficient. In addition, to account for the potential occurrence of a ''sticking condition'' (sliding occurs by shear fracture of the softer of the two materials, rather than by a relative motion at the contact interface), a maximum value of shear stress (equal to the shear strength of the softer material) that can be transmitted at any level of the contact pressure is also specified [36]. It should be noted that, in order to account for the presence of yarn coating (not modeled explicitly), a low value of the friction coefficient l = 0.05 was used [8].…”

Section: Contact Interactionsmentioning

confidence: 99%

The effect of plain-weaving on the mechanical properties of warp and weft p-phenylene terephthalamide (PPTA) fibers/yarns

et al. 2014

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Coarse-grained molecular statics/dynamics methods are first used to investigate degradation in the PPTA fiber/yarn tensile strength, as a result of the prior compressive or tensile loading. PPTA fibers/yarns experience this type of loading in the course of a plain-weaving process, the process which is used in the fabrication of ballistic fabric and flexible armor. The more common allatom molecular simulations were not used to assess strength degradation for two reasons: (a) the size of the associated computational domain rendering reasonable run-times would be too small and (b) modeling of the mechanical response of multi-fibril PPTA fibers could not be carried out (again due to the limited size of the computational domain). However, all-atom simulations were used to (a) define the coarse-grained particles (referred to as ''beads'') and (b) parameterize various components of the bead/bead force-field functions. In the second portion of the work, a simplified finite-element analysis of the plain-weaving process is carried out in order to assess the extent of tensile-strength degradation in warp and weft yarns during the weaving process. In this analysis, a new material model is used for the PPTA fibers/yarns. Specifically, PPTA is considered to be a linearly elastic, transversely isotropic material with degradable longitudinal-tensile strength and the longitudinal Young's modulus. Equations governing damage and strength/stiffness degradation in this material model are derived and parameterized using the coarse-grained simulation results. Lastly, the finite-element results are compared with their experimental counterparts, yielding a decent agreement.

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“…Ceramic layers are most often joined with other layers absorbing the energy, by the adhesive bonding method [1]. In literature the stress is put on the role of adhesive joints in the shaping of protective properties of multilayer armours [5,7]. For instance the research [7] indicated that for a twin-layer amour (Aluminium oxide/aluminium), there is an optimum thickness of the adhesive layer (0.3 mm), where the effectiveness of the armour is the highest.…”

Section: Introductionmentioning

confidence: 99%

Investigation of ballistic resistance of adhesive bonded multi-layer structures

Godzimirski¹,

Rośkowicz²,

Komorek³

2017

EiN

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The role of adhesive in the ballistic/structural performance of ceramic/polymer–matrix composite hybrid armor

Cited by 94 publications

References 20 publications

Wind-Turbine Gear-Box Roller-Bearing Premature-Failure Caused by Grain-Boundary Hydrogen Embrittlement: A Multi-physics Computational Investigation

Wind-Turbine Gear-Box Roller-Bearing Premature-Failure Caused by Grain-Boundary Hydrogen Embrittlement: A Multi-physics Computational Investigation

The effect of plain-weaving on the mechanical properties of warp and weft p-phenylene terephthalamide (PPTA) fibers/yarns

Investigation of ballistic resistance of adhesive bonded multi-layer structures

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