Stone Protective Solutions, LLC (SPS) has developed a patent-pending blast-resistant laminated wood panel technology that can be applied to the manufacturing and/or upgrade of blast-resistant modular (BRM) units that need to meet safety design requirements from accidental explosions or security Anti-Terrorism design requirements from bomb attacks. Our new 8 PSI Enviro BRM with a combination of steel and wood laminated panels are far more environmentally amiable to manufacture and are considerably ergonomically friendlier than steel BRMs. SPS has also tasked Stone-OBL, LLC to blast test the patent-pending blast-resistant laminated wood panel technology. Two tests were performed at the Stone-OBL blast testing site located in Deschutes County, Oregon near Bend, Oregon. An existing reinforced concrete reaction structure was supplemented with a rigid steel frame and plate system to accommodate the test panel, as shown in Figure 1.
Figure 1: Blast-Resistant Wood Laminated Panel within Stone-OBL Concrete Reaction Structures
The explosive charges used in the testing program were equivalent to car and truck bomb threats with different standoff distances for each test. The performance of the laminated wood panel during these tests were recorded using sensors and normal and high speed cameras. The ranges of gauge readings recorded for positive phase pressure and impulse are presented in Table 1. Figure 2 and Figure 3 show photographs of the panel following Test 1 and Test 2, respectively.
Table 1 – Reflected Blast Pressure Gauge Readings
|Test Number||Pressure in psi (kPa)||Impulse in psi-ms (kPa-ms)|
|1||33-35 (230-240)||90-103 (620-710)|
|2||25-28 (170-190)||96-123 (660-850)|
Figure 2: Post-Test 1 Exterior (left) and Interior (right)
Figure 3: Post-Test 2 Exterior (left) and Interior (right)
The maximum displacement of the panel did not exceed 0.4 inches (10 mm) for either test within the first 150 ms of recorded response. Moreover, no damage or permanent panel deformation was observed, in either case, during post-test inspection (i.e., the panel returned to its original pre-test position resulting in an elastic response). As such, wood laminated panels with a similar through-thickness lay-up and span can likely sustain significantly higher blast loads than those tested, prior to achieving permanent deformation. The panels can potentially take even higher loads for applications where permanent panel deformation is acceptable (e.g., where panels are subjected to a one-time blast event and only need to sustain capacity to allow for personnel egress).