This paper presents the effects of truck vibration and packaging systems on the bruising of apples. The study investigated four different types of interior packaging : the foam tray, the paper pulp tray, and t w o different paperboard partition/box combinations. Testing was done on a vibration table using a random controller driven by a power density spectrum simulating truck trailers with leaf-spring and air-cushion suspensions travelling on expressways. The results showed that the foam tray was the best type of interior packaging followed by the paperboard partitions. The paper pulp tray produced the highest levels of damage. The air-cushion truck suspension showed larger damage levels than the leaf-spring suspension for all package types.
Keywords: Apple bruising; truck vibration damage; interior packaging
I NTRO D U CTlO NApples packaged commercially undergo a series of shocks as a result of handling and transportation. Every process from picking of the fruit to distribution to the consumer offers an opportunity for bruises, cuts, or punctures. Various studies have been done to determine the effects of picking, handling, and transportation on damage.'-3 Armstrong4 evaluated the effect of vibration on apple bruising in bulk bins. The results showed that the stiffness of the bin bottom played a critical role in establishing the resonant behaviour of the bin and apple system. Schulte et aL5 investigated the effect of intrastate shipments on damage to 'Golden Delicious' apples. His results showed that shipment conditions that cause impacts above 20G in the paper pulp tray-masters are critical to damage and should be avoided.This study investigated the effect of packaging and trailer suspension types using random vibration to simulate the shipping environment. The use of random vibration for package performance testing has become increasingly important since the damaging effects can be significantly greater than for purely sinusoidal vibration, which up to now has been the norm for laboratory simulation of the transportation environment.6 With the introduction of ASTM Standard D 4728, packaging engineers can now use recommended power density spectrums to simulate changing vibration levels in various transportation systems. Figures 1 and 2 show the two power density spectrums used in this study. These spectra were developed from real-time vibration measurements on trailers with leaf-spring and air-cushion suspensions, respectively, travelling on interstate expressways.' The 'good air ride' and 'damaged air ride' spectra shown in Figure 2 correspond to a properly maintained air-suspension system (with required air pressure) and a poorly maintained one (low air pressure and possible leaks) respectively. All testing was done using the 'good air ride' spectrum. Bruise results for the 'damaged air ride' spectrum are expected to be
In order to meet the cost requirement of lateral and longitudinal velocity measured directly in vehicle active safety control systems, based on 3-DOF vehicle model and the Recursive Least Squares (RLS) which can identify the tire cornering stiffness online, a control algorithm using Extended Kalman Filter(EKF) to estimate lateral and longitudinal velocity is proposed. The estimation values are compared with simulator values from CarSim. The compared results demonstrated that the proposed algorithm could estimate the lateral and longitudinal velocity accurately and robustly.
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