Blast Resistant Panels Research Articles

Experimental and Numerical Investigation of the Mechanical Properties of a Fiber-Reinforced Geopolymer Mortar Blast Resistant Panel.

Geopolymer materials have excellent properties such as high strength, low thermal conductivity, fire resistance, acid and alkali resistance, and low carbon emissions. They can be used as protective engineering materials in places with explosion risks. At present, the common composite blast resistant panel is in the form of a sandwich: the outer layer isgalvanized steel plate, and fiber cement board or calcium carbonate board is used as the inner layer material, as these boards have the advantages of easy installation, good fire resistance, and explosion resistance. This study investigates the effect of adding different types of fibers to geopolymer mortar on the mortar's basic mechanical properties, such as compression strength, bending strength, and impact resistance. The explosive resistance of the fiber-reinforced geopolymer mortar blast resistant panels was evaluated through free-air explosion. In this paper, experimental procedures and numerical simulation have been performed to study the failure modes, maximum deflection, and dynamic response of the fiber-reinforced geopolymer mortar blast resistant panel under free-air explosion. The research results can provide a reference for the design and production of blast resistant panels.

Motion-based design approach for a novel variable friction cladding connection used in wind hazard mitigation

Cladding systems typically serve architectural purposes and protect occupants against the external environment. It is possible to leverage these systems to enhance structural resiliency. A common application is the use of blast resistant panels for enhanced protection against man-made hazards, whereas energy is dissipated through sacrificial elements. However, because these protection systems are passive, their mitigation capabilities are bandwidth limited, therefore targeting single types of hazards. The authors have recently proposed a novel variable friction cladding connection (VFCC), which enables the leveraging of cladding inertia for mitigating blast, wind, and seismic hazards. The variation in the friction force is generated by an actuator applying pressure onto sliding friction plates via a toggle system. Previous work has characterized the dynamic behavior of a VFCC prototype, and established design procedures for blast mitigation applications. Here, work is extended for applications to wind mitigation. An analytical model is developed to characterize the dynamic behavior of the VFCC for wind-induced vibrations. A motion-based design framework is developed to enable an holistic integration of the device within the structural design phase. Numerical simulations are conducted on a 24-story building example to demonstrate the motion-based design methodology. Results show that the semi-active cladding system provides significant reduction in the wind-induced inter-story drift and floor acceleration, therefore demonstrating the promise of the VFCC for field applications.

Assessing through-thickness damage propagation, impact tests on layered composite beams - experimental work and numerical simulation

The growing applications of layered fiber reinforced composite materials lead to the potential use of such lightweight materials for blast and ballistic impact resistant panels. Under such high strain rate loading, through-thickness damage propagation is crucial for the structural integrity of the panels. Experiments performed in composite panels under blast loading exhibited little information for the understanding of the time-line of damage propagation as only post-mortem inspection can be done. Instrumentation may be installed in order to follow the blast but the task reveals itself arduous as all the instruments must be protected against the blast. The sparse information can be valuable for configuration screening purposes, but is not su ffi cient for comparison and validation of numerical models. The work focuses on performing controlled impact experiments in narrow beams filmed side-wise with high-speed cameras. The narrow geometry of the beams leaves the thickness of the specimen exposed to the cameras allowing for a real-time monitoring of the stress waves propagating and for assessing the time-line of through-thickness damage propagation onset. Results showed that polyethylene impactors, given the right diameter, are the most suitable soft impactors. Numerical models including in-plane and out-of-plane damage propagation are being built in order to replicate the experimentally observed damage. The ultimate goal being establishing design rules for such lightweight fiber reinforced panels. It is numerically observed that, the speed propagation of delamination in the longitudinal direction reaches a common constant value for all interfaces.

An inverse mapping capability for designing blast resistant composite panels through multi-scale modelling

This paper presents the development of a multi–scale simulation process for modelling the response of a composite panel to blast loads from an explosive threat. The new process can be used for improving the blast resistant capabilities of the composite panel by configuring its properties at the microlevel. A multi–scale simulation process using the coupled MAC/GMC and ABAQUS explicit codes for computing the response of a structure subjected to a load from an explosion has been established. The functionality of this multiscale simulation capability and the efforts in incorporating microconstitutive material behaviour at high strain rate loading in the simulation process are presented. Formulating an inverse mapping capability for linking desired material properties with the composition of their micro structure in MAC/GMC in a computationally efficient manner, and conducting an optimisation analysis for identifying the desirable material properties for increasing the blast resistant characteristics are presented.

Integrated design of blast resistance panels and materials

In modern armour warfare, crew survivability is of paramount importance. One way to ensure survivability is to protect soldiers from anti-tank mines with Blast Resistant Panels (BRPs). A BRP is a lightweight sandwich structure with a low-relative-density core in between two high-density panels.The aim of this project is to further enhance the performance of BRPs using lighter structures, in order to mitigate the kinetic energy induced by shock waves. We employ a new design approach, using integrated material and a product design which utilizes a distributed framework. This approach eliminates the inherent limitations of pre-designed materials used in conventional, material-selection-based design. In this context, the limitations of BRPs designed in the conventional approach are examined and compared with the new BRP design. An artificial neural network-based material model is introduced to demonstrate the practicality and feasibility of this new design paradigm. The BRP design is then validated using FEA.Design results of the new BRP are compared to those using the conventional material-selection-based design.

Model refinement decisions using the process performance indicator

Model refinement is crucial to managing complexity in the design of complex engineered systems, particularly in the context of integrated product and materials design. In order to manage complexity, a systematic approach for model refinement is presented in this article. The approach is based on a value-of-information-based process performance indicator (PPI). The systematic approach and indicator can also be used to make refinement decision using multiple models when, for example, models are refined through model replacement. Both are particularly well-suited for integrated product and materials design, and other scenarios where perfect knowledge of the true system behavior and error-bounds is not available throughout the entire design space. In this article, the proposed approach is applied to model refinement for designing multifunctional blast resistant panels (BRPs). It is shown that the proposed approach based on the PPI is useful for model refinement particularly when accuracy of the prediction or the associated error bounds is not known.

Ductal – A High-Performance Material for Resistance to Blasts and Impacts

Reactive Powder Concrete (RPC) is a cementitious material consisting of cement, sand, silica fume, silica flour, superplastiser, water and high strength steel fibres. The material, developed by Bouygues the parent company of VSL, is marketed under the brand name of Ductal®. Production in Australia commenced in early 2003. Ductal is almost self placing, has a compressive strength of 160–200 MPa and a flexural strength of 30–40 MPa. In structural applications, Ductal is generally used without any passive reinforcement. Very fine high strength steel fibres are able to withstand secondary tensile stresses. Prestressing counterbalances the main tensile stresses due to bending. The durability properties of Ductal and its resistance to aggressive agents are orders of magnitude better than conventional high performance concrete. A predicted design life in marine environments of several hundred years is achievable. The unique characteristics of Ductal, including exceptionally high energy absorption capacity and resistance to fragmentation, make it ideal for panels and components that need to perform under explosives, impact or shock loads. The flexural toughness is greater than 200 times that of conventional fibre reinforced concrete. In May 2004, the performance of seven Ductal panels was evaluated in two large explosive trials performed at Woomera (South Australia). The panels performed remarkably well, exhibiting high levels of ductility and no signs of fragmentation. In further tests, 100mm thick Ductal blast resistant panels have been shown to effectively resist impacts by blast produced fragments using fragment simulated projectile tests. These panels can also withstand impacts from the highest class of rifle projectiles in the Australian Standard AS 2343. In June 2005, the first Ductal protective panels manufactured to provide resistance to blast were supplied to the Australian Government and installed on an Australian Government building in a high risk international location.