In this investigation, a T-shaped aluminum alloy isogrid stiffener element used in aerospace applications was inspected with ultrasonic phased array methods. The isogrid stiffener element had various crack configurations emanating from bolt holes. Computational simulation methods were used to mimic the experiments in order to help understand experimental results. The results of this study indic...

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 ...

The design of stiffened, composite wing panels must satisfy a range of requirements related to performance, economy and safety. In particular, the design must be damage tolerant to satisfy a number of different performance requirements for various states of damage. To obtain an optimum configuration that satisfies these requirements simultaneously, optimization code PANOPT was extended with a m...

Beam-type stiffeners have frequently been used for raising natural frequencies of baseline structures. In stiffener layout optimization problems, most of the previous researches considering the position and/or the length of the stiffener as design variables dealt with structures having just simple convex shapes such as a square or a rectangle. The reason was because concave shape structures hav...

Worldwide, the pace of development in pedestrian countermeasures is increasing rapidly. To better understand the state of the art in bumper design for pedestrian impact, a survey of literature and patents has been performed. Two general approaches to reducing the severity of pedestrian lower limb impacts were identified: (a) Provide cushioning and support of the lower limb with a bumper and a n...

To investigate the influence of end-plate stiffeners on the initial rotational stiffness of extended end-plate internal joints, an experimental program was carried out to investigate the rotational behavior of the joints. Two finite element methods (FEMs) were proposed using ABAQUS software. The stress distribution, plastic development, and deformation characteristics of extended end-plate join...

Abstract—The present work illustrates a parametric study for the effect of stiffeners on the performance of slender built up steel Icolumns. To achieve the desired analysis, finite element technique is used to develop nonlinear three-dimensional models representing the investigated columns. The finite element program (ANSYS 13.0) is used as a calculation tool for the necessary nonlinear analysi...

In this paper, load-carrying capacity in steel shear wall (SSW) was estimated using artificial neural networks (ANNs). The SSW parameters including load-carrying capacity (as ANN’s target), plate thickness, thickness of stiffener, diagonal stiffener distance, horizontal stiffener distance and gravity load (as ANN’s inputs) are used in this paper to train the ANNs. 144 samples data of each of th...

In the present research, behavior of SPSPs with two rectangular openings and effect of strengthening different subpanels with various stiffener arrangements is investigated. In the next step, to investigate the effect of changing opening width on the trend of degradation shear stiffness and strength of the panel, the opening width is changed. In the third step, to study the effect of changing o...

Abstract Multi-stiffener composite panels are the primary components widely used in aircraft structures such as fuselage, wing box, and rear bulkhead, but they typically sensitive to compressive load-induced buckling thin-walled nature of these components. This paper presents a numerical experimental study on failure behaviour multi-stiffener panels. A progressive damage model based Hashin’s cr...