Protection Effect on a Ballistic Impact of NATO 7.62 Ball Bullet into Helicopter Drive Shaft: Numerical Simulation

2011 ◽  
Vol 82 ◽  
pp. 710-715 ◽  
Author(s):  
Davide Lumassi ◽  
Andrea Manes ◽  
Marco Giglio
Keyword(s):  
Finite Element ◽  
Power Transmission ◽  
Numerical Models ◽  
Deformable Body ◽  
Numerical Procedure ◽  
Experimental Tests ◽  
Ballistic Impact ◽  
Drive Shaft ◽  
Constitutive Law ◽  
The Impact

Actual strategies and rules in peace keeping mission have led to an intensive use of helicopters exposing the aircraft and the crew to significant risks. Typical missions in fact involve low altitude flights in hostile environment where many threats can cause severe damages, leading eventually to the loss of the machine and the crew. According to this scenario, the tail rotor power transmission is one of the most critical components for its fundamental role to ensure flight stability and for its vulnerability, being very exposed during flight manoeuvre. In addition light weapons are wide spread, due to their cheapness and manoeuvrability. So the impact of 7.62x61 NATO ball 9.5 g bullet is an event anything but remote. This projectile is a full metal jacket bullet, with a brass jacket and a lead alloy core. Due to its mechanical characteristics, the soft lead core undergoes to high deformations and failures (mushroom and debris) during the impact, causing a large and extensive damaged area. Several researches have been developed to investigate the ballistic impact of conventional bullet against typical thin and lightweight aeronautical structure. As usual in this field, a complete methodology with experimental tests and numerical approaches has been carried on. In particular Finite Element analyses, although require complicate calibrations and validation which can be only made through indispensable experimental tests, represent a key resource. Very detailed numerical models are an extremely powerful tool to investigate the damage generated during an impact and allow simulating complex and extreme cases. With this premises direct impact between a 7.62x51 NATO ball 9.5 g bullet with a tube simulating an Helicopter drive shaft has been investigated by the authors in a previous work both with experimental and numerical activities with good agreement. However, considering the huge effect of bullet deformation verified during this activity, the modification of the bullet due to a preliminary impact with the surrounding frame (around the shaft in the real helicopter) could influence in a remarkable way the damage shape and extension in the shaft. This is an issue that is worth to further investigation and this is the aim of this paper. Basing only on a numerical procedure, previously assessed, an investigation of the impact of a NATO 7.62x51 mm ball 9.5 g bullet into an Al-6061-T6 pipe and its protection is presented. In particular the work will focus on the influence of the frame panel, which covers the transmission shaft, on the impact conditions. Analysis are carried out using the Finite Element commercial code ABAQUS/Explicit. Advanced materials’ descriptions, constitutive law and fracture criterion are introduced within the numerical model of the shaft and protection; projectile has been modelled as deformable body. Different impact conditions have also been tested in order to identify the worst impact condition.

Reverse Engineering of Experimental Tests Results of Ballistic Impact for the Validation of Finite Element Simulations

2010 ◽  
Author(s):  
Andrea Manes ◽  
Grazia Magrassi ◽  
Marco Giglio ◽  
Monica Bordegoni
Keyword(s):  
Finite Element ◽  
Reverse Engineering ◽  
Numerical Models ◽  
Real Data ◽  
Experimental Tests ◽  
Engineering Practice ◽  
Explicit Finite Element ◽  
3D Acquisition ◽  
Set Up ◽  
The Impact

In this paper the set up and the carrying out of experimental ballistic tests on a tail rotor transmission shafts for helicopter, which are impacted by a 7.62 NATO projectile, are presented. After the tests, a 3D acquisition of the impacted area on each shaft has been performed in order to acquire exactly the shape of the damage. The acquisition has been carried out with a 3D range camera. The experimental activities have been compared with the results of a numerical simulation of the impact, which has been computed with an explicit finite element code. The direct comparison has been done by superimposing the two meshes (from FE analysis and from 3D acquisition). This method has proved to be effective for identifying analogies and differences and for giving the possibility to promote a “quantitative” discussion with the aim of improving the accuracy of the numerical models and simulation conditions. The adoption of the Reverse Engineering practice has proved to be a powerful method for integrating and comparing the simulation data with real data, and give suggestions to further analysis.

A Numerical Procedure for the Virtual Compression after Impact Analysis

2015 ◽  
Vol 24 (4) ◽  
pp. 096369351502400 ◽  
Author(s):  
Rosario Borrelli ◽  
Stefania Franchitti ◽  
Francesco Di Caprio ◽  
Fulvio Romano ◽  
Umberto Mercurio
Keyword(s):  
Finite Element ◽  
Impact Analysis ◽  
Numerical Models ◽  
Numerical Procedure ◽  
Composite Plates ◽  
Low Velocity Impact ◽  
Finite Element Code ◽  
Research Activity ◽  
Compression After Impact ◽  
The Impact

The aim of the proposed research activity is to investigate on the structural behaviour of composite plates in order to develop numerical models able to describe their damage resistance to impact loads and their damage tolerance through compression after impact (CAI) test. The present paper presents a two-step simulation approach for determining the residual strength after a low velocity impact on a composite laminate of aeronautical interest. The first step is aimed at determining the damage extent after the impact event and it is performed by using an explicit finite element code. Hence, the damage status induced by the impact is transferred to the finite element model for the virtual compression after impact test which is simulated in a second step by using an implicit finite element code. Numerical results, in terms of force vs. displacement impact curve, damage envelope and reaction vs. applied strain compression curve, were compared to the experimental ones for validation purpose.

Experimentally validated predictive finite element modeling of the V0-V100 probabilistic penetration response of a Kevlar fabric against a spherical projectile

2018 ◽  
Vol 9 (4) ◽  
pp. 504-524 ◽  
Author(s):  
Gaurav Nilakantan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Finite Element Modeling ◽  
Element Model ◽  
Ballistic Impact ◽  
Impact Testing ◽  
Woven Fabric ◽  
Projectile Impact ◽  
Element Modeling ◽  
The Impact

This work presents the first fully validated and predictive finite element modeling framework to generate the probabilistic penetration response of an aramid woven fabric subjected to ballistic impact. This response is defined by a V0-V100 curve that describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this article comprises a single-layer, fully clamped, plain-weave Kevlar fabric impacted at the center by a 0.22 cal spherical steel projectile. The fabric finite element model comprises individually modeled three-dimensional warp and fill yarns and is validated against the experimental material microstructure. Sources of statistical variability including yarn strength and modulus, inter-yarn friction, and precise projectile impact location are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, each comprising unique mappings. The impact velocities and outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve obtained from ballistic impact testing and shown to be in excellent agreement. The experimental data and its statistical analysis used for model input and validation, namely, the Kevlar yarn tensile strengths and moduli, inter-yarn friction, and fabric ballistic impact testing, are also reported.

NUMERICAL AND EXPERIMENTAL APPROACH FOR THE OPTIMAL DESIGN OF A DUAL PLATE UNDER BALLISTIC IMPACT

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1538-1543
Author(s):  
JEONGHOON YOO ◽  
DONG-TEAK CHUNG ◽  
MYUNG SOO PARK
Keyword(s):  
Numerical Simulation ◽  
Optimization Technique ◽  
Mesh Size ◽  
Experimental Tests ◽  
Ballistic Impact ◽  
Plastic Energy ◽  
Dual Plate ◽  
Element Erosion ◽  
Parameter Values ◽  
The Impact

To predict the behavior of a dual plate composed of 5052-aluminum and 1002-cold rolled steel under ballistic impact, numerical and experimental approaches are attempted. For the accurate numerical simulation of the impact phenomena, the appropriate selection of the key parameter values based on numerical or experimental tests are critical. This study is focused on not only the optimization technique using the numerical simulation but also numerical and experimental procedures to obtain the required parameter values in the simulation. The Johnson-Cook model is used to simulate the mechanical behaviors, and the simplified experimental and the numerical approaches are performed to obtain the material properties of the model. The element erosion scheme for the robust simulation of the ballistic impact problem is applied by adjusting the element erosion criteria of each material based on numerical and experimental results. The adequate mesh size and the aspect ratio are chosen based on parametric studies. Plastic energy is suggested as a response representing the strength of the plate for the optimization under dynamic loading. Optimized thickness of the dual plate is obtained to resist the ballistic impact without penetration as well as to minimize the total weight.

scholarly journals Experimental and Numerical Analysis of the Tendon Repair Process Using Tubular Braided Fabrics

2018 ◽  
Vol 18 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Jerry Ochola ◽  
Benny Malengier ◽  
Lode Daelemans ◽  
John Githaiga ◽  
Lieva Van Langenhove
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Modelling ◽  
Flexor Tendon ◽  
Numerical Models ◽  
Tendon Repair ◽  
Experimental Tests ◽  
Repair Process ◽  
Flexor Tendon Repair ◽  
Element Modelling

AbstractThis paper presents the experimental and numerical analysis of the potential of a braided fabric for flexor tendon repair. Numerical models of tubular braided fabrics were generated using a python script interface and imported into ABAQUS®while Flexor tendon models were represented as silicone rubber rods. Experimental tests and Finite Element Modelling (FEM) of the flexor tendon repair was undertaken by deploying two tendon ends from opposite sides of a tubular braided fabric. This was done such that the tendon ends meet at the midpoint within the fabric. The tendons were tightly held to emulate a realistic repaired tendon. A displacement driven uniaxial loading was induced on the tendon-fabric assembly sufficient to cause a 2mm gap between the tendon ends. Numerical analysis of the repair potential of a braided fabric in tendon repair was done by analyzing selected fabric parameters that were crucial in tendon repair applications. The results show that changing the parameters of the braided fabrics significantly affected the potential of the fabrics during tendon repair.

scholarly journals Experimental and Numerical Analysis of Recovery Stress in Ni47Ti44Nb9 Shape Memory Alloys: Application to Tightening

2010 ◽  
Author(s):  
Boris Piotrowski ◽  
Etienne Patoor ◽  
Tarak Ben-Zineb ◽  
Andre Eberhardt
Keyword(s):  
Finite Element ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Experimental Tests ◽  
Constitutive Law ◽  
Recovery Stress ◽  
Test Bed ◽  
Home Test ◽  
Niti Sma ◽  
Transformation Hysteresis

Ni47Ti44Nb9 Shape Memory Alloys (SMAs) are widely considered for tightening applications. The alloy is composed of a NiTi SMA matrix containing niobium precipitates. A specific thermomechanical treatment strongly increases the transformation hysteresis in these alloys, what improves the tightening efficiency. Tightening pressures exhibited by Ni47Ti44Nb9 rings are experimentally investigated. Strain gage measurements allow to monitor the tightening pressure using a home test bed. Evolutions with temperature are recorded. A thermo-mechanical constitutive law, specific for Ni47Ti44Nb9, is proposed. It is based on the Mori-Tanaka scale transition technique by considering the precipitates as elastic-plastic inclusions embedded in the SMA matrix. The resulting effective law is implemented, and validated in ABAQUS via UMAT subroutine. Experimental tests are simulated by Finite Element Modeling, and comparisons are performed.

Assessment of the Realistic Stiffness and Capacity of the Connections in Quincha Frames to Develop Numerical Models

2013 ◽  
Vol 778 ◽  
pp. 526-533 ◽  
Author(s):  
Natalie Quinn ◽  
Dina D’Ayala
Keyword(s):  
Finite Element ◽  
Numerical Models ◽  
Experimental Tests ◽  
Element Model ◽  
Accurate Representation ◽  
Timber Frame ◽  
Historic Structures ◽  
The World ◽  
Infill Material ◽  
High Degree

Peru is one of the most seismically active countries in the world, this fact highlighted by several destructive earthquakes in recent years. The centre of Lima has a large number of historic structures with a ground floor in adobe, and their upper storeys in quincha, a traditional technique consisting of a timber frame with an infill of canes and mud. Despite the existence of a large number of buildings containing this technique, very little is known about its seismic performance. In order to investigate this, a series of experimental tests on quincha frames, with and without the infill, have been carried out previously, with the aim of quantifying the lateral behaviour and identifying vulnerable areas. The present paper details work carried out to develop a finite element model of the test frames without infill. This model of the timber frame will enable an accurate representation of the frame behaviour to be developed before adding the infill of canes and mud to the model. As the behaviour of the infill material and its connection to the frame is difficult to determine, characterising the timber frame with a high degree of accuracy ensures that the contribution of the infill can be globally quantified from the overall experimental results. The beams and posts are connected by cylindrical mortice and tenon joints, with a diagonal bracing member providing some lateral restraint. The connections have been modelled semi-rigid springs, with the stiffness calculated using variations of the component method. This was found to give very similar results to those obtained experimentally.

Ballistic penetration damages and energy absorptions of stacked cross-plied composite fabrics and laminated panels

2020 ◽  
Vol 29 (9) ◽  
pp. 1465-1484
Author(s):  
Qingsong Wei ◽  
Bohong Gu ◽  
Baozhong Sun
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Impact Damage ◽  
Ballistic Impact ◽  
Body Armor ◽  
Element Analysis ◽  
Laminated Panels ◽  
Composite Fabrics ◽  
The Impact ◽  
Ballistic Penetration

Flexible fabrics have been widely used in body armor designs. Here we report ballistic impact damage of stacked cross-plied composite fabric and cross-plied laminated panels. The ballistic impact behaviors of stacked cross-plied composite fabric and cross-plied laminated panel have been tested with fragment-simulating projectiles under the strike velocity 550–600 m/s to explore the influence of the layers combination of fabric target on ballistic impact. Two types of macroscopic anisotropy continua finite element models based on fabric targets structures are established to analyze the ballistic mechanism of stacked cross-plied composite fabric and cross-plied laminated panels. The impact damage morphologies and energy absorptions have also been compared between the tests and finite element analysis results. We have found the stacked fabric construction absorbed more energy than their counterpart cross-plied laminated panel, while the laminated panel shows better structural integrity and stability during ballistic penetration.

A Numerical Simulation on Ballistic Penetration Damage of 3D Orthogonal Woven Fabric at Microstructure Level

2011 ◽  
Vol 21 (2) ◽  
pp. 237-266 ◽  
Author(s):  
Xiwen Jia ◽  
Baozhong Sun ◽  
Bohong Gu
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Impact Damage ◽  
Experimental Tests ◽  
Woven Fabric ◽  
Stress Wave Propagation ◽  
Rigid Projectile ◽  
Microstructure Model ◽  
3D Orthogonal Woven ◽  
The Impact

The ballistic impact damages of 3D orthogonal woven fabric (3DOWF) penetrated under a conically cylindrical rigid projectile were investigated from experimental tests and finite element simulations. A microstructure model of the 3DOWF was established and imported into finite element geometrical preprocessor. In the microstructure model, the architecture of the 3DOWF has the same spatial configurations with that of the real 3DOWF, including the spatial distributions and cross-sections of warp, weft yarns, and Z-yarns. Mechanical parameters of the yarns were obtained from high-strain rate tests which near to the impact loading condition in ballistic tests. The impact damage evolutions of the 3DOWF were simulated with the commercial finite element code ABAQUS/Explicit. From the comparisons of damage morphologies and residual velocities of the projectile after perforation between experimental and finite element simulation, it was found that the simulation can reflect the impact damage precisely. Furthermore, the stress wave propagation and damage mechanisms can be revealed from the microstructure model. Insights gained from this study will prove extremely useful in further material and architectural studies that will ultimately lead to optimization of the 3DOWF structure.

Finite Element Simulations and Experimental Investigations of Simple 2-D Geometries in Slamming

2008 ◽  
Author(s):  
Adrian Constantinescu ◽  
Alain Neme ◽  
Nicolas Jacques ◽  
Philippe Rigo
Keyword(s):  
Finite Element ◽  
Water Surface ◽  
Free Water ◽  
Experimental Tests ◽  
Experimental Investigations ◽  
Convergence Criterion ◽  
Numerical Work ◽  
Fluid Structure ◽  
The Impact ◽  
Good Agreement

This paper presents a numerical and experimental study of fluid structure interaction during the impact of a solid body on a water surface. The main request is the modeling of the slamming forces acting on the ship structure in severe sea conditions. The numerical work uses the finite element modeling of a structure impact with free water surface. The first analysis use the commercial finite element code ABAQUS/Standard and combines the assumption of small displacements for the ideal fluid and the solid with an asymptotic formulation for accurate pressure evaluation on the boundary of the wet surface. For deformable strickers, two methods are developed. The first method employs a weak fluid-structure coupling. The second method, more accurate, uses an implicit fluid-structure coupling using a convergence criterion. The second analysis is represented by the simulations of slamming with ABAQUS/Explicit. The simulation uses a viscous, compressible fluid and a soft-exponential law to manage the contact between fluid and solid. The results in term of pressure and total effort applied to the rigid structure are in good agreement with first numerical results and especially with the FLUENT CFD. In order to validate the numerical methods, slamming experimental tests were carried out with a new hydraulic shock press at the ENSIETA laboratory.

Sign in / Sign up

Export Citation Format

Share Document