scholarly journals Effectiveness of Banana Trunk as Protection Wall from High Velocity Shrapnel During Detonation of Unexploded Ordnance (UXO)

2021 ◽  
Vol 2129 (1) ◽  
pp. 012006
Author(s):  
Abdul Rashid Othman ◽  
Ahmad Humaizi Hilmi ◽  
Asna Rasyidah Abdul Hamid ◽  
Wong Xian Jun
Keyword(s):  
High Energy ◽  
Unexploded Ordnance ◽  
Energy Impact ◽  
Improvise Explosive Device ◽  
Banana Fibre ◽  
Velocity Of Detonation ◽  
Stereo Microscope ◽  
Explosive Remnants Of War ◽  
High Energy Absorption ◽  
The Impact

Abstract This paper is to investigate banana trunk fibre to be constructed alternatively for the sand bag and high energy absorption. The aim of this study also for enhancing method of absorption velocity shrapnel during detonated of Unexploded Ordnance (UXO), Explosive Remnants of War (ERW) and Improvise Explosive Device (IED). The study involved blast test which is providing high energy impact based on the amount of explosive used. Type of explosive were used are Emulex 180 with velocity of detonation 4500m/s to 5700m/s, Explosive energy 4.17 MJ/kg, density 1.13g/cc to 1.21g/cc and initiation were used are No. 8 Detonator. The structure of specimen is analysed using Stereo Microscope Image Analyser (35x zoom) which is an optical instrument that can observe the structure of the fragments (banana fibre) after blast test. Results shows that banana trunk can become a protection wall as it can absorb the impact of blast from explosion.

An Enhanced Time-Reversal Method for Impact Damage Monitoring on Plate-Like Structures

2012 ◽  
Vol 525-526 ◽  
pp. 365-368
Author(s):  
Chun Lin Chen ◽  
Yu Long Li ◽  
Fuh Gwo Yuan
Keyword(s):  
Time Reversal ◽  
Composite Structures ◽  
Impact Damage ◽  
High Energy ◽  
Low Velocity ◽  
Energy Impact ◽  
Location Detection ◽  
Focusing Property ◽  
The Impact ◽  
Impact Events

Based on the self-focusing property of time-reversal (T-R) concept, a time focusing parameter was suggested to improve the impact source identification method developed in authors previous work. This paper presents a further study on monitoring relatively high energy impact events which caused induced damage on structures. Numerical verifications for a finite isotropic plate and a composite plate under low velocity impacts are performed to demonstrate the versatility of T-R method for impact location detection with induced plastic deformation and delamination damage on metallic and composite structures respectively. The focusing property of T-R concept was adequately utilized to detect impact/damage location. The results show that impact events with various features can be localized using T-R method by introducing the time focusing parameter. It is suited to monitor serious impact events on plate like structures in practice in future.

Impact Response of Circular Tube with Concentric Plunger

2013 ◽  
Vol 275-277 ◽  
pp. 792-798
Author(s):  
Amir Radzi Ab Ghani ◽  
Hafizi Lukman ◽  
Hafizan Hashim
Keyword(s):  
Energy Absorption ◽  
Circular Tube ◽  
High Energy ◽  
Absorption Capacity ◽  
Peak Force ◽  
Impact Response ◽  
Impact Performance ◽  
High Energy Absorption ◽  
The Impact ◽  
Initial Peak

Thin-walled tubes are generally used as impact energy absorber in various application due to their ease of fabrication and installation, high energy absorption capacity and long stroke. However, the main drawback of plain tube is the high initial peak force. A concentric plunger in the form of tapered block is proposed to overcome this shortcoming while at the same time, improving the impact performance. Static and dynamic axial crushing were performed to determine the initial peak force (IPF), crush force efficiency (CFE) and specific energy absorption (SEA) for the concentric plunger with various taper angles. It was found that the concentric plunger affected the tube impact response. Comparison with plain circular tube was carried out and it was found that the concentric plunger improved the impact response of the tube especially in term of initial peak force.

Containment and Arrest of Blade Shedding in Gas Turbine Engines Using Novel Dual-Ring Design

2021 ◽  
Author(s):  
Prayers Roy ◽  
Shaker A. Meguid
Keyword(s):  
Energy Absorption ◽  
Impact Damage ◽  
Impact Resistance ◽  
High Energy ◽  
Element Analysis ◽  
Single Ring ◽  
High Energy Absorption ◽  
Interfacial Gap ◽  
The Impact ◽  
Dual Ring

Abstract In this paper, we examine the energy absorption and containment capabilities of a newly proposed dual-ring design accounting for interactions between a released blade and fully bladed fan disk using 3D finite element analysis. The components of this dual-ring design are strategically selected to ensure high energy absorption and high impact resistance, thus leading to reduced damage of the disk and increased safety. Three containment ring designs are examined: (i) conventional single-ring design composed of one of titanium, aluminum or Kevlar, (ii) a newly proposed aluminium-Kevlar dual-ring arrangement, and (iii) dual-ring arrangement with an interfacial gap between them to arrest and contain the released blade and ensure free passage of the trailing blades. The results of our numerical simulations indicate that although the single-ring design resists penetration and contains the released blade within the confines of the disk, it does not remove the released blade from the path of the trailing blades leading to severe damage to the fan disk. On the contrary, our new dual-ring design, which contains an interfacial gap, has potential to successfully arrest the released blade within the confines of the ring and out of the path of the trailing blades. This design significantly can reduce the impact damage to the fan disk and reduces kinetic energy of the released blade to near zero in less than half a rotation of the fan disk.

Impact Resistance of SM Joints Formed With ICA

2002 ◽  
Vol 124 (4) ◽  
pp. 374-378 ◽  
Author(s):  
C. M. Lawrence Wu ◽  
Robert K. Y. Li ◽  
N. H. Yeung
Keyword(s):  
Impact Damage ◽  
Impact Resistance ◽  
High Energy ◽  
Bending Test ◽  
Conductive Adhesives ◽  
Energy Impact ◽  
Split Hopkinson ◽  
Post Impact ◽  
Impact Bending ◽  
The Impact

Isotropic conductive adhesives (ICA) have been considered as replacement materials for lead-tin solder alloys. In this paper, the post-impact shear strength of ICA surface mount (SM) joints was obtained experimentally and compared with that of SM lead-tin joints. The dynamic impact energy was provided in the form of three-point bending on the PCB using equipment called the split Hopkinson bar. Strain rates of over 4000/s were used for the impact bending test. The action of impact bending was used to simulate the effect on the PCB and the interconnection as a result of high energy impact on an electronic equipment. Shear test was then performed to examine the change in strength of the ICA joints as a result of impact damage. It was found that the SM ICA joints failed due to impact at a strain rate just over 4000/s. Microstructural examination carried out using a scanning electron microscope revealed that the interface between the ICA and copper pad on the PCB was the weakest region of the joint.

Effect of Parameter Optimization of Contact Force Models on the Impact Dynamic Responses

1993 ◽  
Author(s):  
H. M. Lankarani ◽  
F. Wu
Keyword(s):  
Energy Absorption ◽  
Contact Force ◽  
Multibody System ◽  
High Energy ◽  
Contact Forces ◽  
Dynamic Responses ◽  
Particle Model ◽  
Force Model ◽  
High Energy Absorption ◽  
The Impact

Abstract Reducing the severity of an impact to a structure or a multibody system is a significant aspect of engineering design. This requires the knowledge of variations of the resulting contact forces and also how these contact forces can be reduced. This paper presents an optimization methodology for the selection of proper parameters in the contact/impact force models so as to minimize the maximum value of the contact force. A two-particle model of an impact between two solids is considered, and then generalized to the impact analysis between two bodies of a multibody system. The concept of effective mass is presented in order to compensate for the effect of joint forces or impulses. The system is reduced to a single degree-of-freedom mass-spring-damper vibro-impact system. A single differential equation of motion in the direction of relative indentation of local contact surfaces is derived. Different contact force models of hysteresis form including linear and nonlinear models are described. An optimization problem is then formulated and solved by using the method of modified feasible direction for constrained minimization. A numerical integrator is used at every design iteration to obtain the system dynamic response for a given set of design variables. The objective function is to minimize the peak acceleration of the system equivalent mass resulting from the contact force. Comparison of the system with optimal parameters and non-optimal one shows that the peak contact force is greatly reduced for the optimal one. Since these parameters reflect the material properties (stiffness and damping) of the impacting bodies or surfaces, suitable materials may then be selected based upon the information provided by this optimization procedure. It is observed that the materials, which have good crashworthiness properties should posses capability of dissipating impact energy both in the forms of permanent indentation and internal damping friction. Based upon the analysis of the impact responses, mechanism of energy dissipation, and the typical force-indentation diagram for the high energy absorption materials obtained from experiments, a new contact force model is proposed which could precisely describe the impact response of high energy-absorption materials.

scholarly journals Normalization of the extragalactic background light from high-energy γ-ray observations

2019 ◽  
Vol 627 ◽  
pp. A110
Author(s):  
B. Biasuzzi ◽  
O. Hervet ◽  
D. A. Williams ◽  
J. Biteau
Keyword(s):  
Galaxy Formation ◽  
A Priori ◽  
Diffuse Radiation ◽  
Far Infrared ◽  
High Energy ◽  
Extragalactic Background Light ◽  
Background Light ◽  
Spectrum Radio ◽  
High Energy Absorption ◽  
The Impact

Extragalactic background light (EBL) plays an important role in cosmology since it traces the history of galaxy formation and evolution. Such diffuse radiation from near-UV to far-infrared wavelengths can interact with γ-rays from distant sources such as active galactic nuclei (AGNs), and is responsible for the high-energy absorption observed in their spectra. However, probing the EBL from γ-ray spectra of AGNs is not trivial due to internal processes that can mimic its effect. Such processes are usually taken into account in terms of curvature of the intrinsic spectrum. Hence, an improper choice of parametrization for the latter can seriously affect EBL reconstruction. In this paper, we propose a statistical approach that avoids a priori assumptions on the intrinsic spectral curvature and that, for each source, selects the best-fit model on a solid statistical basis. By combining the Fermi-LAT observations of 490 blazars, we determine the γ-ray-inferred level of EBL for various state-of-the-art EBL models. We discuss the EBL level obtained from the spectra of both BL Lacs and flat spectrum radio quasars (FSRQ) in order to investigate the impact of internal absorption in different classes of objects. We further scrutinize constraints on the EBL evolution from γ-ray observations by reconstructing the EBL level in four redshift ranges, up to z ∼ 2.5. The approach implemented in this paper, carefully addressing the question of the modeling of the intrinsic emission at the source, can serve as a solid stepping stone for studies of hundreds of high-quality spectra acquired by next-generation γ-ray instruments.

Use of External Testing Methods to Assess Damage on Rockfall Protection Structures

2011 ◽  
Vol 82 ◽  
pp. 704-709 ◽  
Author(s):  
Adeline Heymann ◽  
Marielle Collombet ◽  
Stéphane Lambert ◽  
Philippe Gotteland
Keyword(s):  
Large Deformations ◽  
High Energy ◽  
Seismic Velocities ◽  
Testing Methods ◽  
Energy Impact ◽  
Rockfall Protection Structures ◽  
The Impact ◽  
Topographic Surveys ◽  
Rockfall Protection ◽  
Geophysical Measurements

This paper deals with the evaluation of damage due to boulder impact on rockfall protection embankment thanks to external methods. A 4 m high, 8 m long three layered structure is built using cells filled with different material according to their location in the structure. The structure is impacted by a 6500 kg spherical boulder with a maximal impact energy of 2000 kJ. The behaviour of the structure is first investigated using topographic surveys. Then, the results are compared with geophysical measurements. Results show that a low-energy impact leads to (i) the densification of both front and inner-layers associated with the swelling of the materials of the rear layer in the impact plane, and (ii) to the readjustment of internal materials which induces a local densification in a plane offset of 2 m. A high-energy impact induces large deformations on both inner and rear layers. These results are confirmed by seismic velocities which decrease with successive impacts.

scholarly journals Experimental Investigation of Impact Localization in Composite Plate Using Newly Developed Imaging Method

2018 ◽  
Author(s):  
Mohammad Faisal Haider ◽  
Asaad Migot ◽  
Md Yeasin Bhuiyan ◽  
Victor Giurgiutiu
Keyword(s):  
Composite Plate ◽  
High Energy ◽  
Temperature Cycle ◽  
Imaging Method ◽  
Impact Event ◽  
Scanning Method ◽  
Time Frequency ◽  
Energy Impact ◽  
The Impact ◽  
Impact Localization

This paper focused on impact localization of composite structures, which possess more complexity in the guided wave propagation because of the anisotropic behavior of composite materials. In this work, a composite plate was manufactured by using a compression molding process with proper pressure and temperature cycle. Eight layers of woven composite prepreg were used to manufacture the composite plate. A structural health monitoring (SHM) technique is implemented with piezoelectric wafer active sensors (PWAS) to detect and localize the impact on the plate. There are two types of impact event are considered in this paper (a) low energy impact event (b) high energy impact event. Two clusters of sensors recorded the guided acoustic waves generated from the impact. The acoustic signals are then analyzed using a wavelet transform based time-frequency analysis. The proposed SHM technique successfully detect and localize the impact event on the plate. The experimentally measured impact locations are compared with the actual impact locations. An immersion ultrasonic scanning method was used to visualize the composite plate before and after the impact event. A high frequency 10 MHz 1-inch focused transducer was used to scan the plate in the immersion tank. Scanning results show that there is no visible manufacturing damage in the composite plate. However, clear impact damage was observed after the high-energy impact event.

Characterization of Resin-Injection Repair of Impact Damage in Polymer Matrix Composite

2015 ◽  
Author(s):  
Ritwik Prashant Moghe ◽  
Raghu V. Prakash ◽  
Deepika Sudevan ◽  
Hema Katta Shambhayya
Keyword(s):  
Polymer Matrix ◽  
Impact Damage ◽  
Damage Zone ◽  
Injection Pressure ◽  
High Energy ◽  
Low Energy ◽  
Repair Method ◽  
Energy Impact ◽  
Resin Injection ◽  
The Impact

Resin injection repair of impact damage in polymer matrix composites is studied using an in-house developed repair methodology. Carbon fiber reinforced polymeric composite specimens were impacted for three levels of impact damage (23 J, 35 J and 51 J — typical of low energy, medium energy, high energy) using a drop tup test rig and the damage zone was characterized using ultrasonic C-scan technique. The impact damaged specimens were repaired using a resin infiltration method. The selection of low viscosity room temperature curing resin, and process parameters such as resin injection pressure and vacuum levels to be maintained were studied to arrive at optimum repair method. The tension, compression strength of laminates prior to impact and post-impact as well as post-repair was studied to assess the quality of repair method. The results indicate that the chosen resin injection repair is effective for the repair of low energy impact damage but not in the case of medium and high energy impact damage.

High-Energy Impact Certification of Aero Structures: Experiments and Numerical Simulations

2015 ◽  
Vol 237 ◽  
pp. 233-238
Author(s):  
Grzegorz Socha ◽  
Sebastian Szałkowski ◽  
Andrzej Zbrowski
Keyword(s):  
Numerical Simulations ◽  
Impact Resistance ◽  
Experimental Tests ◽  
High Energy ◽  
Sustainable Technologies ◽  
Impact Tests ◽  
Energy Impact ◽  
Particle Hydrodynamics ◽  
Real Objects ◽  
The Impact

The article presents the test results obtained from the “Research methods and systems for the investigation on impact resistance of elements of aero structures and land vehicles aimed at the assessment of passenger safety” R&D project that was jointly executed by the Institute of Aviation, the Institute for Sustainable Technologies – National Research Institute, and the PZL Mielec. The main objective of the project was to perform impact tests of the windscreen and the vertical stabilizer of the PZL M28 Skytruck. The experimental tests were conducted for real objects in full scale. The investigations were carried out using an original 250 mm pneumatic gun. Apart from the impact tests, the project was also focused on numerical simulations of impacts employing the Finite Element Method (test object modelling) and the Smoothed Particle Hydrodynamics methods (the model of the gelatine projectile). The authors compare the results of experimental tests and numerical simulations. They present the differences in the results obtained and analyse the reasons behind these discrepancies, and based on the analysis, they conclude that the main cause for them is the simplified mathematical model describing the behaviour of the material subjected to dynamic loads, which was used in numerical simulations.

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