In the present paper, an algorithm is presented for reliability analysis of beams with random material properties under static spatially random loads. The randomness may be due to the employed manufacturing process that leads to components with slightly different microstructures. Since the material properties are random, the stiffness matrices and subsequently, the response will be of random natures. On the other hand, majority of the service loads of some structures, e.g. airplanes, vehicles, and machining equipments are random. Therefore, special techniques should be utilized. In the present paper, variability of the response is determined and discussed through various examples. The proposed algorithm is extended to include a stress-based analysis. Finally, reliability of the beam is evaluated in the treated examples.

Watermelon is handled and stored in bulk package as some other fruits and vegetables are. Package height must be so appropriately selected that bottom fruit layers will receive no damage or failure. This research was performed to determine and compare the mechanical properties of two varieties in three sizes of watermelon under static load conditions to obtain parameters used in transportation as well as in storage. A statistical factorial experiment in the form of a completely randomized design (2×3×2) of five replications was employed to determine the mechanical properties of watermelon in whole watermelon. Such factors as failure force, failure deformation and fruit rind thickness were among those determined. It is found that the failure force was affected by the direction in which it was exerted. Failure force in the longitudinal direction was less than that in the transverse direction while variation in size of the fruit did not significantly affect either failure force or failure deformation. Results also indicated that failure force and failure deformation were significantly affected by variety. Mean failure forces for Charleston Gray and Crimson Sweet varieties were 1.1 and 1.8 kN, respectively. Investigation of rind thickness in different varieties and sizes of watermelon demonstrated that five millimeter increase in rind thickness can increase failure force up to 70%.

Iran is a major world producer of walnuts and a hub of walnut exports to other countries. Walnut harvesting and cracking is still done manually, which increases price and waste. Design and development of an effective harvester and walnut crusher is required to reduce costs and wastage. This study determined the mechanical properties of a test apparatus employing two flat jaws using different treatments and walnut varieties. Testing was done on three varieties of walnuts at two speed loads (30 and 50 mm/min) in three directions (one vertical and two horizontal). A universal testing machine was used to determine the rupture force, rupture energy and toughness for Hartley, Z63 and Z30 walnut varieties. Results showed that the effect of variety and loading direction was significant at the 0.01 level and the effect of load speed was significant at the 0.05 level for rupture energy and toughness. The triple effect was not significant. Result shows that increasing loading speed increased rupture energy and rupture force and decreased toughness.

The mechanical strength of cumin seed and the effects of moisture content, seed size, speed and direction of loading on the force and energy required to fracture cumin seed were investigated. The results showed that moisture and loading direction were significant at the 1% level on the force and energy required to fracture cumin seed. The effects of seed size on force and loading speed on energy were also significant at the 1% level. Increasing moisture content decreased mechanical strength and increased elasticity under loading. The energy absorption capacity of wet seed was higher than that of dry seed and led to increased seed strength under loading. The highest energy absorption (15.31 mJ) was found for small seeds at 15% moisture content under horizontal loading and the lowest energy absorption (1.72 mJ) was found for large seeds at 5.7% moisture content under vertical loading. Small seeds with 5.7% moisture content under horizontal loading had the highest mechanical strength and large seeds at 15% moisture content under vertical loading had the lowest mechanical strength.

In this paper at first introduced constituent equations for piezoelectric and then by the help of this equations, internal energy of hinged-hinged piezoelectric multilayer beam was computed. Then by the principle of minimum potential energy and Rayleigh -Ritz method the bending curvature equation of hinged-hinged piezoelectric multilayer beam under concentrated moment, concentrated force, uniform pressure load and applied electrical voltage with satisfaction of boundary conditions are guessed. Unknown coefficients are determined by the principle of minimum potential energy. Thereinafter obtained equations have simplified for hinged-hinged unimorph and bimorph beam. Electrical load and voltage produced in unimorph and bimorph beam as sensor are calculated. In order to verify the derived equations for a hinged-hinged piezoelectric multilayer bending beam, the analytical calculation compared with ANSYS 10 results by some finite element examples.