Wood pallets are increasingly stored in warehouses with drive-in or drive-through racks. A pallet needs adequate stiffness and strength to function safely under conditions where it spans the rack support rails. When the stringers run parallel to the supports, the fasteners reinforce the deckboard load-carrying ability. This report experimentally determines the effect of fasteners on pallet performance. The effect is characterized in terms of the ratio of the joint rotation modulus to a normalized deckboard bending stiffness. This approach enables the joints to be compared with pinned and rigid joints in a pallet stiffness and strength theory.

A brief account is given of the principles of dual-energy computerized tomography (DECT) and of the potential which DECT has demonstrated for the automated detection of commercial and military explosives concealed in suitcases or packages. A description of a breadboard system configured for this purpose is provided and recent advances in the state of the art in CT are discussed in the light of their potential significance for explosives detection.

Alloys of iron-aluminum-manganese containing over 8% aluminum can be made completely austenitic and have good ductility and toughness. Oxidation resistance is good at temperatures up to 982°C (1800°F), but embrittlement occurs following heating in the range 538 to 760°C (1000 to 1400°F). Resistance to corrosion by aqueous environments is poor.

Fracture toughness δi of AISI 4340 steel in the hardened and tempered condition has been determined by the multiple-specimen CTOD (crack tip opening displacement) resistance curve method. This fracture toughness δi value has been compared with the JIc fracture toughness also obtained by the multiple-specimen JR curve technique. The investigation also examines the effect of specimen size, thickness, and width on δi and δR curve behavior. The effect of these parameters on the constraint factor m in the J-δ relationship has also been examined. Compact tension specimens with TL orientation were used. All specimens satisfied ASTM E 813 standard size requirements. This investigation demonstrates that Jδi values obtained by the CTOD resistance curve method are similar to JIc values obtained from the J-integral resistance curve method. The specimen thickness has no significant influence on δi or δR curve behavior. On the other hand, specimen width has a distinct influence on constraint factor m and δR curve behavior.

Traditional equations for determining shear modulus for beams are based on several simplifying assumptions. Although these assumptions are reasonably accurate for isotropic homogenous beams, they can introduce large errors when applied to beams of structural lumber that are not isotropic or homogeneous. This paper examines the sensitivity of the traditional equations to various parameters and concludes that the edition of 1983 and the previous editions of ASTM Methods for Static Tests of Timbers in Structural Sizes (D 198) were not suitable for determination of shear modulus in structural lumber. An alternative test method currently used in Europe was proposed. Based on the considerations in this paper, this method was adopted in the 1984 edition of ASTM D 198.