Ultrasonic inspection has been widely used to detect defects in composite materials such as internal discontinuity, cracks, delaminations, inclusions, lack of bond etc. However when the bonded specimen has small thickness, the echo from the defect region makes it difficult to identify the echo from the unflawed· region. To overcome these disadvantages, different statistical pattern recognizing ...

This paper presents a study of the possibilities of evaluating thermal parameters of single and multilayer structures using dynamic thermography. It also discusses potential uses of lock-in thermography. It presents a simulation of a periodic excitation of a multilayer composite material. In practice, the described methods can be employed in various applications, for example, in multilayer nonw...

fiber/ metal laminates (fmls) are hybrid composites consisting of alternating thin layers of metal sheets and fiber reinforced epoxy laminates. in this study, the effect of fiber orientation on impact properties of fml plates is investigated both analytically and experimentally. two groups of specimens were prepared and tested in two different levels of impactor energy. the indentation depth an...

SUMARY: The variability of properties in composite materials and structures is an origin of a scatter in failure loads. In the present paper we propose a non-stochastic description of uncertainity effects that allows us to evaluate lower and upper bounds of failure loads understood in the sense of buckling, FPF and delaminations. The vertex method is introduced and discussed herein to evaluate ...

This paper employs an atomic-scale finite element method AFEM to study the postbuckling behavior of carbon nanotubes CNTs . The computed energy curves and critical strain for the 8, 0 single-walled CNT SWNT agree well with atomistic simulations. The AFEM is very fast and versatile owing to the efficiency of the finite element method. For the SWNT, the strain energy curves have obvious jumps at ...

OBJECTIVE The purpose of this in vitro study was to explore the radiopacity of composite resins and bonding materials using film and phosphor plates. METHODS Nine composite dental resin specimens and human tooth slices were exposed together with an aluminium stepwedge using dental film and phosphor plates. Eight dentin bonding specimens were prepared and exposed in a similar manner. Their rad...

Fiber reinforced polymer (FRP) composites are getting a wide range of application areas in bridge rehabilitations because these materials are less affected by corrosive environmental conditions, known to provide longer life and require less maintenance. However, there are still some concerns about their long-term performance because currently limited data exists. Moreover, the quality control a...

This paper proposes the refined first order shear deformation theory to investigate the free vibration behavior of bidirectional functionally graded porous plates. This theory satisfies the transverse shear stress free conditions at the top and bottom of the plate, thus avoids the need of a shear correction factor. The rule of mixtures is employed to compute the effective material properties an...