طراحي، ساخت و ارزيابي دستگاه شاخه تكان و تعيين بهترين دامنه و بسامد بر ريزش بهار نارنج

چكيده انگليسي :

۸۴Design Development and Evaluation of a Limb Shaker Mechanism and Determination of the Best Amplitude and Frequency of Sour Orange Blossom Detachment Azadeh Sarafraz Sarafraz d@gmail com May 22 2011 Department of Agricultural Machinery Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Aminallah Masoumi masoumi@cc iut ac irAbstractBlossom of Sour orange tree is used in producing perfume but the primary application is in the shape ofdry blossom especially as liquid extracts In herbal medicine Sour orange blossom is a relaxation agentand anti anxiety and disorder in nervous system and reduces nervous headache and migraine as well Considering economic value of sour orange blossom blossom has been harvested each year at a specifictime Hand harvesting of blossom requires time and increases costs and may result in tree injury On theother hand use of tree trunk shakers has problems because of size weight and high power requirement Inthis investigation a unique and precise logically programmable electro pneumatic limb shaker of impacttype was designed and developed to mechanically harvest sour orange blossom The hand held shakerwas pneumatically powered and driven by a rechargeable air compressor and electric motor The shakerconsisted of these parts impact gripper boom pneumatic actuator metal strap frequency changing knob programmable logic controller PLC and pneumatic valve To reduce transfer of vibration from shaker tooperator s hand a metal hand strap was shaped in a way that was hinged to the tree while working and atthe same time transferring some of the weight of the shaker In order to design the shaker physical andmechanical properties of sour orange tree were investigated and vibration force for detachment of theblossom from the branch was determined In order to determine the vibration force vibration system ofbranch shaker was presumed with one degree of freedom The branch was presumed to be a cantileverbeam and natural frequencies of beam were determined The static force of sour orange blossomdetachment was determined using universal testing machine The developed machine had the ability toprovide three levels of shaking amplitude 20 30 and 40 mm at oscillating frequencies of 1 2 3 4 5and 6 hertz By combining any of the three amplitude levels with four levels of shaking frequency themost suitable combination to obtain maximum orange blossom removal percentage with least damagecould be obtained Harvesting rate was calculated by weighing both the harvested and unharvested orangeblossom A 3 4 factorial experiment with completely randomized block design with four replications wasconducted to investigate the effects of shaking amplitude and frequency on blossom detachment Experiments were conducted in the orchards of Dezful Jolgedez CO in Khuzestan Province Iran In thisexperiment four levels of frequency 1 2 3 and 4 hertz three levels of amplitude 20 30 and 40 mm were investigated The analysis of variance and mean comparison conducted with SAS and MSTAD Cand results obtained showed that the effect of shaking frequency and amplitude and interacting effectswere significant on sour orange blossom detachment Harvesting rate of the shaker increased with anincrease in frequency but additional increase in frequency had no effect on blossom removal percentage Reduction in amplitude resulted in an increase in vibration force on the tree branch and blossom removalpercentage The most suitable shaking frequency and amplitude for harvesting blossom were 4 hertz and20 millimeter respectively which resulted in highest percentage of detachment The dynamic force onthe blossom transferred by dynamic force of shaker was determined at various frequencies andamplitude the value of variation in acceleration versus frequency was obtained from ABAQUS softwareon three point of cantilever tree branch the results show that with distantancing from tree and branchattachment point the acceleration incr

سرافراز، آزاده

طراحي، ساخت و ارزيابي دستگاه شاخه تكان و تعيين بهترين دامنه و بسامد بر ريزش بهار نارنج

خصوصيات مكانيكي چوب , پنوماتيك , كنترولر منطقي , فركانس طبيعي