Delamination multiple

Direct visual inspection of Fig. 4 shows that, an astonishingly much larger amount of energy is consumed in the laminated material at moderate tension. The reason for this could be that the extension of LDPE requires multiple fracture of the Al-foil or delaminating. Multiple fracture of the Al-foil would consume a large amount of energy. 

No observations of crack-branching or multiple delamination propagation (common in multidirectional lay-ups [2, 5]) in either type of cross-ply laminate have been reported. 

Suemasu H, Majima O. Multiple delaminations and their severity in circular axisym-metrical plates subjected to transverse loadings. J Compos Mater 19% 30(4) 441—53. 

Aymerich E, Dore E, Priolo P. Simulation of multiple delaminations in impacted cross-ply laminates using a finite element model based on cohesive interface elements. Compos Sci Technol 2009 69 1699-709. 

Gronnd penetrating radar (GPR) is an electromagnetic technique that has been nsed for many years with the engineering industry to supply information on construction and condition detail of various types of structure. GPR also known as impulse radar gives valuable information on the location of reinforcement and can often supply information where cover meters cannot, snch as lapping bars, multiple layers and tendon ducts behind cover reinforcement. There has already been some discussion of its application for delamination measurement in Section 4.6. 

In (a), the minimum critical resolved shear stress [henceforth CRSS] is 36 MPa. In (b), deformation occurs by a combination of delamination and kink-band formation in individual grains and also by shear-band formation. The multiple modes of deformation allow for plastic behavior in any arbitrary orientation of the compressive load. Notice that the 312- and 211-phases are layered hexagonal carbides and nitrides, having the general formula Mn+iAXn, (MAX), where n = 1 to 3, M is an early transition metal, A is an A-group element (mostly III A and IV A, or groups 13 and 14) and X is either carbon and/or nitrogen. 

As mentioned above the initial fracture toughness of Pe/epoxy is lower (ca. 300 J/m2) than for Kevlar, 1100 J/m. This means that multiple delaminations have to occur in the Dyneema system in order to get a similar impact slope. 

An interwoven triangular truss core with face sheets is shown in Figure 9.28. A double interwoven truss core with face sheets is shown in Figure 9.29. The integrally woven cells were made to reduce the delamination of the composite materials and to enable them to withstand multiple impacts. 

Another limitation is posed by the shadowing effect in PMC. The delamination closest to the transducer will reflect the ultrasonic pulse to such an extent that delaminations below will be masked, unless their lateral size is larger. Even C-scans taken on both sides do not necessarily guarantee detection of delaminations in all layers. In the reflection mode, repeat echoes from multiple reflections have to be distinguished from real indications, especially in relatively thin PMC shells. 

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