This numerical study investigates the effect of cross section geometry on the bending of a beam and also buckling of a column made of shape memory alloy (SMA). It incorporates superelastic SMA's non-linear stress-strain relations, including the nonsymmetric behavior in tension and compression. Primarily, an arbitrary rectangular cross section is selected for analysis of the beam and column, loaded beyond the linear stress-strain relations. Then similar analysis is carried out for two different equivalent cross sections, namely, square of same area and square of same inertia, for comparing the effect of cross section geometry on the response of the beam and column. Using the equations of static equilibrium, the variations of effective modulus and bending moment for different equivalent cross sections are presented. The critical stress of the column is calculated by assuming an appropriate deflection curve for both ends hinged condition. It is found that the effective modulus depends only on the stress-strain curve. The bending moment, on the other hand, is a function of the stress-strain curve and cross section geometry. For a given load, the square of same area develops the minimum bending stress, while the square of same inertia develops the maximum bending stresses. Because of the non-symmetric stress-strain curve, the compressive stress is found to be higher than the tensile stress. It is also found that the buckling load for a column is distinctly high if the non-symmetric stress-strain curve is used in the analysis. Moreover, for a very high critical stress, the square of same area has the highest slenderness ratio, while the rectangle has the lowest slenderness ratio.

Undescended testis is a common risk factor for the testicular neoplasm. The risk of malignancy in an undescended testis is highest when the testis lies in the abdomen. It usually presents with a painless intraabdominal lump. Seminoma is the most common adult germ cell tumour of testis whereas Yolk sac tumour in seen in the pediatric age group. Pure yolk sac testicular tumor in an adult is extremely uncommon. Here we present a case where an adult male presented to us with a painless left sided intraabdominal lump with undescended testis on the same side was previously diagnosed as metastatic adenocarcinoma of unknown primary. In a private hospital he received three cycles of chemotherapy; but the lump did not reduce in size and he was reffered to our care for better management. The lump was excised and histopathological report revealed yolk sac tumour of left testis which is a rare presentation in adult. J Shaheed Suhrawardy Med Coll, December 2018, Vol.10(2); 115-117