This work presents the robustness assessment of stiffened thin-walled composite structures in postbuckling, which is based on a new design strategy that satisfies weight, load-based performance and energy-based robustness requirements. In this approach, robustness is understood as collapse insensitivity due a local failure, where global buckling for instance is assumed as a local failure, once ...

A probability-based damage detection algorithm has been implemented in order to identify barely visible impact damages in two composite stiffened panels by means of Acousto Ultrasonics (AU). A modification of RAPID (reconstruction algorithm for probabilistic inspection of defects) has been implemented to adapt the algorithm to the current structures and transducer networks. An improvement of 40...

An analytical investigation is conducted to predict the post-buckling strength of laminated composite stiffened panels under compressive loads. When a stiffened composite panel buckles, the skin would deform into a sinusoidal mode shape, and hence induces additional moments and forces near the skin-stiffener interface region. These induced loads would cause the existing small edge delamination ...

Free vibration behavior of laminated composite plates stiffened by different lattice structures is considered. To simulate free vibration, finite element models were created with Ansys Parametric Design Language (APDL). In the models, SHELL181 and BEAM181 elements used to model structures, respectively. The influence stiffeners on natural frequencies plate examined for clamped-free-clamped-free...

Lightweight and efficient structures have the aim to enhance the efficiency of the components in various industries. Toward this end, composites are one of the most widely used materials because of durability, high strength and modulus, and low weight. One type of the advanced composites is grid-stiffened composite (GSC) structures, which have been extensively considered in aerospace, automotiv...

This paper presents a Bayesian approach for optimizing the position of sensors aimed at impact identification in composite structures under operational conditions. The uncertainty in the sensor data has been represented by statistical distributions of the recorded signals. An optimisation strategy based on the genetic algorithm is proposed to find the best sensor combination aimed at locating i...

A numerical procedure for the design of impact damage resistant composite laminated structures is proposed in the present paper. This procedure, based on probabilistic analyses, is able to support the design of complex composite laminated structures by accounting for the scatter in composite materials’ mechanical properties (related to the mutable environmental conditions experienced by an airc...

The compound strip method (CSM) for plates is an expansion of the finite strip method (FSM) and was developed to incorporate the effects of the support elements in the analysis of linear elastic plate systems. In this paper the CSM is further expanded to analyze structures such as stiffened plates under loads in the plane of the plate or the so called plane-stress condition. Examples of these t...

Optimal design of laminated composite stiffened panels of symmetric and balanced layup with different number of T-shape stiffeners is investigated and presented. The stiffened panels are simply supported and subjected to uniform biaxial compressive load. In the optimization for the maximum buckling load without weight penalty, the panel skin and the stiffened laminate stacking sequence, thickne...