Characterization of low‐acceleration, long‐duration horizontal events using a spring suspension straight delivery box truck

Abstract

A field measurement study, using a combination of controlled and uncontrolled phases, examined low‐acceleration, long‐duration events occurring during over‐the‐road truck transport. A field data recorder equipped with a DC‐based triaxial accelerometer was employed for this study to capture the steady‐state nature of these event types. The field data recorder was rigidly mounted to the trailer chassis to record lateral and longitudinal events of interest. The controlled phase recorded normal and aggressive braking events and traversing a roundabout to fundamentally quantify the behaviour of the vehicle. For the controlled phase, average decelerations of 0.27 and 0.45 g were reported for normal and aggressive braking events, respectively. Lateral accelerations from traversing a roundabout were on average 0.40 g. The uncontrolled field measurement study, which evaluated the transport vehicle over 13 days, reported average longitudinal decelerations and lateral accelerations of 0.29 and 0.34 g, respectively. The rise times associated with these events were also reported. The jerk was calculated based on the rise times for the controlled and uncontrolled phases and compared to currently available test procedures. For both project phases, composite test profiles were developed based on field‐measured levels. The resulting composite test profiles can be utilized to evaluate the load stability of a unit load system travelling through this distribution channel.

Field assessment of horizontal accelerations using air ride suspension trailers

“…Figure 4 displays the frequency of events for all recorded longitudinal events, indicating the majority of all events fall below 0.32 g. These values are significantly less than currently available literature, which states deceleration values as high as 0.8 g in the stopping direction 21 . This study's results align with previous studies that reported average accelerations ranged from 0.27 to 0.33 g for normal braking instances during truck transport 28,29,32 . The CDFs show the percentage of the events that are below a certain measured peak deceleration value.…”

“…The braking application behaviour in the present study is more typical for normal transport conditions. Additionally, the d tr for this study's braking events are significantly longer than previously reported studies, indicating smaller vehicles with lighter payload can achieve shorter rise times 28,31 …”

“…The field measurement study performed encompasses two vehicle sizes using air ride suspension to understand these events better as they occur in standard transport conditions. Since the routes and stopovers of the trips are similar to a prior study, this project intends to compare the obtained data of this project to the prior results of the 26′ straight delivery truck 28 to understand if the suspension and payload affect event rise time and peak acceleration during lateral and longitudinal events. The fundamental knowledge gained from this project will provide insight into the proper test levels for evaluating unit load stability and its components.…”

“…They reported that only 0.11% of brake applications exceeded decelerations greater than 0.4 g. Reports on lateral accelerations have focused on the vehicle driving on a curve or ramp. Harwood et al 27 reported the mean lateral acceleration during on‐ramps to be 0.15 g, but some trucks observed lateral accelerations as high as 0.40 g. A recent study using a spring suspension straight delivery box truck reported average longitudinal decelerations and lateral accelerations of 0.29 and 0.34 g, respectively 28 …”

“…Harwood et al 27 reported the mean lateral acceleration during on-ramps to be 0.15 g, but some trucks observed lateral accelerations as high as 0.40 g. A recent study using a spring suspension straight delivery box truck reported average longitudinal decelerations and lateral accelerations of 0.29 and 0.34 g, respectively. 28 The objective of this research project aims to examine low acceleration long-duration horizontal events. The field measurement study performed encompasses two vehicle sizes using air ride suspension to understand these events better as they occur in standard transport conditions.…”