Permanent indentation and damage creation of laminates with different composite systems: An experimental investigation

Abstract

Quasi-static indentation (QSI) and low-velocity impact tests have been conducted to laminated composite specimens made from different composite systems. C-scan and thermal deply techniques were used to observe the internal damage characteristics of the laminates. The test results show the effect of fibers and matrices on the permanent indentation and damage behaviors of composite laminates. Fiber breakage plays an important role in the formation of permanent indentation and the match between the fiber and matrix also has a significant influence on the permanent indentation and damage behaviors. A comparison shows the correlation between the peak load energy of the QSI tests and the knee point energy of the impact tests, based on which a condition for the prominent indentation formation was proposed for the impact tests. POLYM.

Effects of Kenaf Loading on Processability and Properties of Linear Low-Density Polyethylene/Poly (Vinyl Alcohol)/Kenaf Composites

“…Linear low-density polyethylene (LLDPE), one class of polymer under PE, is widely used in packaging applications; however, its resistance to biodegradation causes environmental pollution (Sam et al 2009;Dikobe and Luyt 2010;Nordin et al 2012). Poly(vinyl alcohol) (PVOH) is a water-soluble biodegradable polymer that is extensively used in packaging applications Rahmah et al 2013). It is well known for its biodegradability and strength, but with the limitation of having low water/humidity resistance and poor processability Azahari et al 2011;Othman et al 2011).…”

“…Nordin et al (2012) reported that blending LLDPE with PVOH is possible, but only at a suitable ratio for optimum properties. Meanwhile, research by Rahmah et al (2013) reported a decrease in tensile strength and an increase in tensile modulus with increasing sago starch (SS) content for hybrid films of linear low-density polyethylene (LLDPE)-sago starch (SS)-poly(vinyl alcohol) (PVOH).…”

Analyzing the nanoindentation response of carbon black filled elastomers

“…Briefly, this concept considers that the unloading process is described by a halfspace with a local distortion of the surface caused by the plastic deformation during the formation of the indentation imprint instead of an elastic contact between the rigid cone and a flat elastic half-space. [20][21][22] Alternatively, the IM approach [Equation ( 3)] provides an alternative method for describing the unloading part of the indentation curve. 22 As shown in Figure 7, the dependences of the indentation depth on force curves are well represented by a power law dependence as expected by the IM approach.…”

“…A number of authors attempted to develop a comprehensive understanding of nanoindentation behavior for CB filled polymer composites. 10,[15][16][17][18][19][20][21] In particular, several studies sought to unravel the correlation between the near-tosurface characteristics of these heterogeneous materials and their macroscale mechanical properties. This was discussed experimentally by comparing properties measured at two scales, 16 or by using multiscale modeling based on the coupling between atomistic and continuum models in order to relate different length and time scales.…”

“…A number of authors attempted to develop a comprehensive understanding of nanoindentation behavior for CB filled polymer composites 10,15–21 . In particular, several studies sought to unravel the correlation between the near‐to‐surface characteristics of these heterogeneous materials and their macroscale mechanical properties.…”