Investigation on Composite Energy Absorbers of a Composite Fuselage Section Subjected to Vertical Drop Test

2019 ◽  
Vol 957 ◽  
pp. 319-328 ◽  
Author(s):  
Donato Perfetto ◽  
A. de Luca ◽  
Giuseppe Lamanna
Keyword(s):  
Load Condition ◽  
Compressive Force ◽  
Structural Response ◽  
Element Model ◽  
Aircraft Industry ◽  
Structural Components ◽  
Crashworthiness Design ◽  
Energy Absorbers ◽  
Composite Energy ◽  
The Impact

In the aircraft industry, crashworthiness design and certification phases have been and are going to be the most attractive topics for designers, mostly because of the increasing use of composites for primary structural components. It is well known that the cargo subfloor elements of the fuselage structure play a crucial role in absorbing the kinetic energy during a crash. In particular, the stanchions, or struts, are important parts for the structural response; as a matter of fact, they connect the fuselage frames to the cabin’s floor and, ideally, are expected to crush under a compressive force in order to dissipate the impact energy in a controlled way and, consequently, to minimize the energy transferred to the passengers. The aim of this work is to demonstrate, experimentally and numerically, the energy absorption capability of the stanchions, made of both composite material and aluminium alloy, of a full-scale 95% composites made fuselage section under a critical load condition, such as an emergency landing. A Finite Element model allowing estimating the passive safety capabilities of the designed struts has been developed and herein proposed.

Numerical and Experimental Investigation on the Energy Absorption Capability of a Full-Scale Composite Fuselage Section

2019 ◽  
Vol 827 ◽  
pp. 19-24 ◽  
Author(s):  
Donato Perfetto ◽  
Giuseppe Lamanna ◽  
M. Manzo ◽  
A. Chiariello ◽  
F. di Caprio ◽  
...  
Keyword(s):  
Finite Element ◽  
Energy Absorption ◽  
Load Condition ◽  
Element Model ◽  
Full Scale ◽  
Research Centre ◽  
Fe Method ◽  
Explicit Finite Element ◽  
Crashworthiness Design ◽  
The Impact

In the case of catastrophic events, such as an emergency landing, the fuselage structure is demanded to absorb most of the impact energy preserving, at the same time, a survivable space for the passengers. Moreover, the increasing trend of using composites in the aerospace field is pushing the investigation on the passive safety capabilities of such structures in order to get compliance with regulations and crashworthiness requirements. This paper deals with the development of a numerical model, based on the explicit finite element (FE) method, aimed to investigate the energy absorption capability of a full-scale 95% composite made fuselage section of a civil aircraft. A vertical drop test, performed at the Italian Aerospace Research Centre (CIRA), carried out from a height of 14 feet so to achieve a ground contact velocity of 30 feet/s in according to the FAR/CS 25, has been used to assess the prediction capabilities of the developed FE method, allowing verifying the response under dynamic load condition and the energy absorption capabilities of the designed structure. An established finite element model could be used to define the reliable crashworthiness design strategy to improve the survival chance of the passengers in events such as the investigated one.

Investigation on Mechanical Properties of Fibreglass Reinforced Flexible Pipes Under Torsion

2018 ◽  
Author(s):  
Pan Fang ◽  
Yuxin Xu ◽  
Shuai Yuan ◽  
Yong Bai ◽  
Peng Cheng
Keyword(s):  
Mechanical Behavior ◽  
Torsion Angle ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Load Condition ◽  
Element Model ◽  
Flexible Pipe ◽  
Torsional Load ◽  
Flexible Pipes ◽  
The Impact

Fibreglass reinforced flexible pipe (FRFP) is regarded as a great alternative to many bonded flexible pipes in the field of oil or gas transportation in shallow water. This paper describes an analysis of the mechanical behavior of FRFP under torsion. The mechanical behavior of FRFP subjected to pure torsion was investigated by experimental, analytical and numerical methods. Firstly, this paper presents experimental studies of three 10-layer FRFP subjected to torsional load. Torque-torsion angle relations were recorded during this test. Then, a theoretical model based on three-dimensional (3D) anisotropic elasticity theory was proposed to study the mechanical behavior of FRFP. In addition, a finite element model (FEM) including reinforced layers and PE layers was used to simulate the torsional load condition in ABAQUS. Torque-torsion angle relations obtained from these three methods agree well with each other, which illustrates the accuracy and reliability of the analytical model and FEM. The impact of fibreglass winding angle, thickness of reinforced layers and radius-thickness ratio were also studied. Conclusions obtained from this research may be of great practicality to manufacturing engineers.

scholarly journals Drop Simulation of 6M Drum With Locking-Ring Closure and Liquid Contents

2006 ◽  
Author(s):  
Tsu-Te Wu
Keyword(s):  
Impact Load ◽  
Three Dimensional ◽  
Structural Response ◽  
Material Model ◽  
Element Model ◽  
Ring Closure ◽  
Foot Drop ◽  
Torque Load ◽  
Three Dimensional Finite Element ◽  
The Impact

This paper presents the dynamic simulation of the 6M drum with a locking-ring type closure subjected to a 4.9-foot drop. The drum is filled with water to 98 percent of overflow capacity. A three dimensional finite-element model consisting of metallic, liquid and rubber gasket components is used in the simulation. The water is represented by a hydrodynamic material model in which the material’s volume strength is determined by an equation of state. The explicit numerical method based on the theory of wave propagation is used to determine the combined structural response to the torque load for tightening the locking-ring closure and to the impact load due to the drop.

scholarly journals Numerical Investigation on Dynamic Response of RC T-Beams Strengthened with CFRP under Impact Loading

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 890
Author(s):  
Huiling Zhao ◽  
Xiangqing Kong ◽  
Ying Fu ◽  
Yihan Gu ◽  
Xuezhi Wang
Keyword(s):  
Numerical Simulation ◽  
Impact Force ◽  
Reaction Force ◽  
Impact Resistance ◽  
Structural Response ◽  
Element Model ◽  
Strengthening Effect ◽  
Strengthened Beam ◽  
Simulation Results ◽  
The Impact

To precisely evaluate the retrofitting effectiveness of Carbon Fiber Reinforced Plastic (CFRP) sheets on the impact response of reinforced concrete (RC) T-beams, a non-linear finite element model was developed to simulate the structural response of T-beams with CFRP under impact loads. The numerical model was firstly verified by comparing the numerical simulation results with the experimental data, i.e., impact force, reaction force, and mid-span displacement. The strengthening effect of CFRP was analyzed from the section damage evaluation. Then the impact force, mid-span displacement, and failure mode of CFRP-strengthened RC T-beams were studied in comparison with those of un-strengthened T-beams. In addition, the influence of the impact resistance of T-beams strengthened with FRP was investigated in terms of CFRP strengthening mode, CFRP strengthening sizes, CFRP layers and FRP material types. The numerical simulation results indicate that the overall stiffness of the T-beams was improved significantly due to external CFRP strips. Compared with the un-strengthened beam, the maximum mid-span displacement of the CFRP-strengthened beam was reduced by 7.9%. Additionally, the sectional damage factors of the whole span of the CFRP-strengthened beam were reduced to less than 0.3, indicating that the impact resistance of the T-beams was effectively enhanced.

Study of Ship-Ice Collision on Ice Breaker ARAON

2014 ◽  
Author(s):  
Sungchan Kim ◽  
Insik Nho ◽  
Takkee Lee ◽  
Kyungsik Choi
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Force ◽  
Structural Response ◽  
Element Model ◽  
Design Data ◽  
Complex Process ◽  
The Impact ◽  
Interaction Behaviors ◽  
Ship Speed

The interaction between a ship and sea ice is a complex process depending on the ice properties, the ice geometry and the relative velocity between the ship and the ice. The effect of important parameters such as ship speed and ice thickness on the impact force are studied by means of finite element model. Idealized ice element types are applied to finite element model in order to survey the impact force and the structural response of icebreaker ARAON subjected to sea ices. Interaction behaviors obtained by finite element model considering the varying parameters are also discussed to compare the numerical results with the design data of ARAON.

Non-Linear Analysis of AP1000 Auxiliary and Shield Building Subjected to Combined Accident Thermal and Seismic Loadings

2014 ◽  
Author(s):  
J. Jennifer Zhang ◽  
Lee J. Tunon-Sanjur
Keyword(s):  
Reinforced Concrete ◽  
Thermal Loading ◽  
Structural Response ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Reduction Factor ◽  
Axial Forces ◽  
Wall Stiffness ◽  
Seismic Loadings ◽  
The Impact

Under the combined accident thermal and seismic loadings, the structural response of the AP1000 Auxiliary and Shield Building (ASB) is numerically investigated. A nonlinear Finite Element Model (FEM) of the AP1000 ASB is developed, in which the rebar in the reinforced concrete is explicitly described and the nonlinear behavior of the concrete is considered. The numerical modeling method and material models used by the reinforced concrete are validated by the testing results published in the literature. The propagation of the thermal loading-induced concrete cracks along the wall thickness is studied. Furthermore, the effects of thermal cracks on the wall stiffness, the development of the thermal stress and the axial forces acting on the reinforcement are fully discussed. The impact of thermal concrete cracks on the design demand of the rebar is also investigated. It is worthy of being further studied how to incorporate the appropriate reduction factor caused by concrete cracks into the linear structural design.

Agricultural aircraft wing slat tolerance for bird strike

2017 ◽  
Vol 89 (4) ◽  
pp. 590-598 ◽  
Author(s):  
Adam Deskiewicz ◽  
Rafał Perz
Keyword(s):  
Finite Element ◽  
Impact Velocity ◽  
Structural Response ◽  
Element Model ◽  
Bird Strike ◽  
Element Analysis ◽  
Content Type ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
The Impact

Purpose The aim of this study is to assess and describe possible consequences of a bird strike on a Polish-designed PZL-106 Kruk agricultural aircraft. Due to its susceptibility to such events, a wing slat has been chosen for analysis. Design/methodology/approach Smooth particle hydrodynamics (SPH) formulation has been used for generation of the bird finite element model. The simulations were performed by the LS-Dyna explicit finite element analysis software. Several test cases have been analysed with differing parameters such as impact velocity, initial velocity vector direction, place of impact and bird mass. Findings Results of this study reveal that the structure remains safe after an impact at the velocity of 25 m/s. The influence of bird mass on slat damage is clearly observable when the impact velocity rises to 60 m/s. Another important finding was that in each case where the part did not withstand the applied load, it was the lug where first failure occurred. Some of the analysed cases indicated the possibility a consequent wing box damage. Practical implications This finding provides the manufacturer an important insight into the behaviour of the slat and suggests that more detailed analysis of the current lug design might improve the safety of the structure. Originality/value Even though similar analyses have been performed, they tended to focus on large transport aircraft components. This investigation will enhance our understanding of structural response of small, low-speed aircraft to a bird impact, which is a realistic scenario for the chosen case of an agricultural plane.

Influence of the distribution of the shear walls on the seismic response of the buildings

2020 ◽  
Vol 15 (1) ◽  
pp. 37-44
Author(s):  
El Mehdi Echebba ◽  
Hasnae Boubel ◽  
Oumnia Elmrabet ◽  
Mohamed Rougui
Keyword(s):  
Structural Analysis ◽  
Seismic Response ◽  
Natural Frequency ◽  
Structural Design ◽  
Structural Response ◽  
Shear Walls ◽  
Structural Elements ◽  
Analysis Software ◽  
Ansys Apdl ◽  
The Impact

Abstract In this paper, an evaluation was tried for the impact of structural design on structural response. Several situations are foreseen as the possibilities of changing the distribution of the structural elements (sails, columns, etc.), the width of the structure and the number of floors indicates the adapted type of bracing for a given structure by referring only to its Geometric dimensions. This was done by studying the effect of the technical design of the building on the natural frequency of the structure with the study of the influence of the distribution of the structural elements on the seismic response of the building, taking into account of the requirements of the Moroccan earthquake regulations 2000/2011 and using the ANSYS APDL and Robot Structural Analysis software.

EXPRESS: Bored, distracted and forgetful – The impact of mind wandering and boredom on memory encoding

2021 ◽  
pp. 174702182110263
Author(s):  
Philippe Blondé ◽  
Marco Sperduti ◽  
Dominique Makowski ◽  
Pascale Piolino
Keyword(s):  
Working Memory ◽  
Memory Load ◽  
Memory Performance ◽  
Load Condition ◽  
Recognition Task ◽  
Mind Wandering ◽  
Memory Encoding ◽  
Working Memory Load ◽  
Thought Probes ◽  
The Impact

Mind wandering, defined as focusing attention toward task unrelated thoughts, is a common mental state known to impair memory encoding. This phenomenon is closely linked to boredom. Very few studies, however, have tested the potential impact of boredom on memory encoding. Thus, the present study aimed at manipulating mind wandering and boredom during an incidental memory encoding task, to test their differential impact on memory encoding. Thirty-two participants performed a variant of the n-back task in which they had to indicate if the current on-screen object was the same as the previous one (1-back; low working memory load) or the one presented three trials before (3-back; high working memory load). Moreover, thought probes assessing either mind wandering or boredom were randomly presented. Afterward, a surprise recognition task was delivered. Results showed that mind wandering and boredom were highly correlated, and both decreased in the high working memory load condition, while memory performance increased. Although both boredom and mind wandering predicted memory performance taken separately, we found that mind wandering was the only reliable predictor of memory performance when controlling for boredom and working memory load. Model comparisons also revealed that a model with boredom only was outperformed by a model with mind wandering only and a model with both mind wandering and boredom, suggesting that the predictive contribution of boredom in the complete model is minimal. The present results confirm the high correlation between mind wandering and boredom and suggest that the hindering effect of boredom on memory is subordinate to the effect of mind wandering.

Investigation on the shaft voltage generation of large synchronous turboalternators

2020 ◽  
Vol 39 (5) ◽  
pp. 1145-1156
Author(s):  
Kevin Darques ◽  
Abdelmounaïm Tounzi ◽  
Yvonnick Le-menach ◽  
Karim Beddek
Keyword(s):  
Finite Element ◽  
Design Methodology ◽  
Short Circuit ◽  
Element Model ◽  
Stator Winding ◽  
Content Type ◽  
Voltage Generation ◽  
The Impact ◽  
Investigation Process ◽  
Circulating Currents

Purpose This paper aims to go deeper on the analysis of the shaft voltage of large turbogenerators. The main interest of this study is the investigation process developed. Design/methodology/approach The analysis of the shaft voltage because of several defects is based on a two-dimensional (2D) finite element modeling. This 2D finite element model is used to determine the shaft voltage because of eccentricities or rotor short-circuit. Findings Dynamic eccentricities and rotor short circuit do not have an inherent impact on the shaft voltage. Circulating currents in the stator winding because of defects impact the shaft voltage. Originality/value The original value of this paper is the investigation process developed. This study proposes to quantify the impact of a smooth stator and then to explore the contribution of the real stator winding on the shaft voltage.

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