Mechanical behavior of rose stems under compressive loading

Knowing the mechanical properties of flower stems is essential for designing automated cut flower processing systems. To determine the crushing force, crushing energy, elastic modulus, and allowable deformation of the stem during the flower transfer and processing process, rose stems were loaded between two parallel plates. The tests were performed at three speed levels (10, 100 and 200 mm/min), two regions of the stem (top of the stem near the flower and bottom of the stem near the root) and different stem diameters (mm). The results indicated that all the parameters mentioned above had a significant effect on the measured mechanical properties (p=0.01). The values ​​of the crushing force and energy for the samples ranged from 35.47 to 15.113 Newton and from 54.29 to 57.104 millijoules. The values ​​of the modulus of elasticity for the different samples were determined from 0.5, 30 to 134.5 MPa. The samples in the lower region had significantly higher force, crushing energy, and modulus of elasticity than the samples in the upper region. With increasing loading speed from 10 to 200 mm/min, the average crushing force and energy per unit area decreased from 84.5 to 62.4 N and from 56.1 to 42.3 mJ/mm2 for the lower group and from 73.1 to 66.8 N and from 33.7 to 20.8 mJ/mm2 for the upper group, respectively.