Investigation of support type effect on plastic hinges in RC beam under impact load

We have tried to develop the simple FE analysis method based on continuum damage mechanics to quantitatively evaluate the impact behaviour and the cumulative damage of RC beam under repeated impact loading. As a result, it has been found that the cumulative damage and residual displacement of RC beam under repeated impact load can be properly evaluated, but the crack propagation cannot be evaluated by using the proposed method. This paper presents the following matters: (1) Numerical investigation on the impact behaviour and cumulative damage of RC beam under repeated impact loading by using the proposed method. (2) Numerical investigation of the relationship between cumulative kinetic energy of repeated impact loading and cumulative damage of RC members. (3) Investigation on improved points of our existing proposed method to evaluate the crack path of RC member under repeated impact.

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Behavior of RC Beams Strengthened by CFRP and Steel Rope under Frequent Impact Load

Journal of Advanced Sciences and Engineering Technologies ◽

10.32441/jaset.001.1.05 ◽

2018 ◽

Vol 1 (1) ◽

pp. 30-42

Author(s):

Muataz Ali ◽

◽

Yaseen Saleh ◽

Luna Al Hasani ◽

Ammar Khazaal ◽

...

Keyword(s):

Impact Load ◽

Rc Beams ◽

Steel Rope

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Fatigue Stress-Life Model of RC Beams Based on an Accelerated Fatigue Method

Infrastructures ◽

10.3390/infrastructures4020016 ◽

2019 ◽

Vol 4 (2) ◽

pp. 16

Author(s):

Eljufout ◽

Toutanji ◽

Al-Qaralleh

Keyword(s):

Cyclic Loading ◽

Fatigue Testing ◽

Three Dimensional ◽

Rc Beam ◽

Rc Beams ◽

Testing Methods ◽

Load Range ◽

Fatigue Stress ◽

Life Model ◽

Prediction Band

Several standard fatigue testing methods are used to determine the fatigue stress-life prediction model (S-N curve) and the endurance limit of Reinforced Concrete (RC) beams, including the application of constant cyclic tension-tension loads at different stress or strain ranges. The standard fatigue testing methods are time-consuming and expensive to perform, as a large number of specimens is needed to obtain valid results. The purpose of this paper is to examine a fatigue stress-life predication model of RC beams that are developed with an accelerated fatigue approach. This approach is based on the hypothesis of linear accumulative damage of the Palmgren–Miner rule, whereby the applied cyclic load range is linearly increased with respect to the number of cycles until the specimen fails. A three-dimensional RC beam was modeled and validated using ANSYS software. Numerical simulations were performed for the RC beam under linearly increased cyclic loading with different initial loading conditions. A fatigue stress-life model was developed that was based on the analyzed data of three specimens. The accelerated fatigue approach has a higher rate of damage accumulations than the standard testing approach. All of the analyzed specimens failed due to an unstable cracking of concrete. The developed fatigue stress-life model fits the upper 95% prediction band of RC beams that were tested under constant amplitude cyclic loading.

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Impact Load Buffering Method Based on Stress Wave Attenuation Principle

International Journal of Applied Mechanics ◽

10.1142/s1758825119500194 ◽

2019 ◽

Vol 11 (02) ◽

pp. 1950019 ◽

Cited By ~ 2

Author(s):

Lin Gan ◽

He Zhang ◽

Cheng Zhou ◽

Lin Liu

Keyword(s):

Stress Wave ◽

Wave Attenuation ◽

Impact Load ◽

Dynamics Simulation ◽

Scanning System ◽

Isolation Method ◽

Element Analysis ◽

System A ◽

High Emission ◽

The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

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Design Optimization of Explosion-Resistant System Consisting of Steel Slab and CFRP Frame

Materials ◽

10.3390/ma14102589 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2589

Author(s):

Jung J. Kim

Keyword(s):

Hybrid System ◽

Impact Load ◽

Load Condition ◽

High Strength ◽

Dynamic Responses ◽

Elastoplastic Behavior ◽

Reinforced Polymer ◽

Steel Slab ◽

Strength Material

This study presents an explosion-resistant hybrid system containing a steel slab and a carbon fiber-reinforced polymer (CFRP) frame. CFRP, which is a high-strength material, acts as an impact reflection part. Steel slab, which is a high-ductility material, plays a role as an impact energy absorption part. Based on the elastoplastic behavior of steel, a numerical model is proposed to simulate the dynamic responses of the hybrid system under the air pressure from an explosion. Based on this, a case study is conducted to analyze and identify the optimal design of the proposed hybrid system, which is subjected to an impact load condition. The observations from the case study show the optimal thicknesses of 8.2 and 7 mm for a steel slab and a ϕ100 mm CFRP pipe for the hybrid system, respectively. In addition, the ability of the proposed hybrid system to resist an uncertain explosion is demonstrated in the case study based on the reliability methodology.

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A Rational Numerical Method for Simulation of Drop-Impact Dynamics of Oleo-Pneumatic Landing Gear

Applied Sciences ◽

10.3390/app11094136 ◽

2021 ◽

Vol 11 (9) ◽

pp. 4136

Author(s):

Rosario Pecora

Keyword(s):

Numerical Method ◽

Initial Conditions ◽

Impact Load ◽

Numerical Models ◽

Landing Gear ◽

Design Stage ◽

Impact Dynamics ◽

State Variables ◽

Adopted Model ◽

The Impact

Oleo-pneumatic landing gear is a complex mechanical system conceived to efficiently absorb and dissipate an aircraft’s kinetic energy at touchdown, thus reducing the impact load and acceleration transmitted to the airframe. Due to its significant influence on ground loads, this system is generally designed in parallel with the main structural components of the aircraft, such as the fuselage and wings. Robust numerical models for simulating landing gear impact dynamics are essential from the preliminary design stage in order to properly assess aircraft configuration and structural arrangements. Finite element (FE) analysis is a viable solution for supporting the design. However, regarding the oleo-pneumatic struts, FE-based simulation may become unpractical, since detailed models are required to obtain reliable results. Moreover, FE models could not be very versatile for accommodating the many design updates that usually occur at the beginning of the landing gear project or during the layout optimization process. In this work, a numerical method for simulating oleo-pneumatic landing gear drop dynamics is presented. To effectively support both the preliminary and advanced design of landing gear units, the proposed simulation approach rationally balances the level of sophistication of the adopted model with the need for accurate results. Although based on a formulation assuming only four state variables for the description of landing gear dynamics, the approach successfully accounts for all the relevant forces that arise during the drop and their influence on landing gear motion. A set of intercommunicating routines was implemented in MATLAB® environment to integrate the dynamic impact equations, starting from user-defined initial conditions and general parameters related to the geometric and structural configuration of the landing gear. The tool was then used to simulate a drop test of a reference landing gear, and the obtained results were successfully validated against available experimental data.

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