Suspension Components Calculation at Concept Stage to Evaluate the Ride and Handling Characteristics

2021 ◽  
Author(s):  
Aliakbar Saifee ◽  
Chandrakant Deshmukh ◽  
Subodh deole
1991 ◽  
Vol 19 (3) ◽  
pp. 122-141 ◽  
Author(s):  
C. Wright ◽  
G. L. Pritchett ◽  
R. J. Kuster ◽  
J. D. Avouris

Abstract A method for determining the effect of suspension dynamics on tire wear has been developed. Typical city cycle maneuvers are defined by instrumented vehicle testing and data in the form of forward velocities and steer angles are used as an input to an ADAMS computer model of the vehicle. A simulation of the maneuvers generates a tire's operating environment in the form of normal load, slip, and camber variations, which contain all the subtle effects of the vehicle's suspension, steering, and handling characteristics. A cyclic repetition of the tire's operating environment is constructed and used to control an MTS Flat-Trac machine. In this way, accelerated tire wear can be generated in the laboratory which is directly related to the design features of the vehicle's suspension and steering systems.


BMJ Open ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. e049098
Author(s):  
Tristan Van Doormaal ◽  
Menno R Germans ◽  
Mariska Sie ◽  
Bart Brouwers ◽  
Andrew Carlson ◽  
...  

ObjectiveThe dural sealant patch (DSP) is designed for watertight dural closure after cranial surgery. The goal of this study is to assess, for the first time, safety and performance of the DSP as a means of reducing cerebrospinal fluid (CSF) leakage in patients undergoing elective cranial intradural surgery with a dural closure procedure.DesignFirst in human, open-label, single-arm, multicentre study with 360-day (12 months) follow-up.SettingThree large tertiary reference neurosurgical centres, two in the Netherlands and one in Switzerland.ParticipantsForty patients undergoing elective cranial neurosurgical procedures, stratified into 34 supratentorial and six infratentorial trepanations.InterventionEach patient received one DSP after cranial surgery and closure of the dura mater with sutures.Outcome measuresPrimary composite endpoint was occurrence of one of the following events: postoperative percutaneous CSF leakage, intraoperative leakage at 20 cm H2O positive end-expiratory pressure or postoperative wound infection. Overall success was defined as achieving the primary endpoint in no more than two patients. Secondary endpoints were device-related serious adverse events or adverse events (AEs), pseudomeningocele and thickness of dura+DSP. Additional endpoints were reoperation in 30 days and user satisfaction.ResultsNo patients met the primary endpoint. No device-related (serious) AEs were observed. There were two incidences of self-limiting pseudomeningocele as confirmed on MRI. Thickness of dura and DSP were (mean±SD) 3.5 mm±2.0 at day 7 and 2.1 mm±1.2 at day 90. No patients were reoperated within 30 days. Users reported a satisfactory design and intuitive application.ConclusionsDSP, later officially named Liqoseal, is a safe and potentially efficacious device for reducing CSF leakage after intracranial surgery, with favourable clinical handling characteristics. A randomised controlled trial is needed to assess Liqoseal efficacy against the best current practice for reducing postoperative CSF leakage.Trial registration numberNCT03566602.


1972 ◽  
Vol 9 (11) ◽  
pp. 759-764
Author(s):  
H. CHEVALIER ◽  
JAMES A. BURKE

Author(s):  
Raj Desai ◽  
Anirban Guha ◽  
P. Seshu

Long duration exposure to vehicle induced vibration causes various ailments to humans. Amongst the various components of the human-vehicle system, the seat suspension plays a major role in determining the level of vibration transferred to humans. However, optimising the suspension for maximising human comfort leads to poor vehicle handling characteristics. Thus, predicting human comfort through various seat suspension models is a widely researched topic. However, the appropriate seat suspension model to be used has not been identified so far. Neither has any prior work reported integrating models of all the components necessary for this analysis, namely human body, cushion, seat suspension and vehicle chassis, each with the appropriate level of complexity. This work uses a two-dimensional 12 DoF seated human body model with inclined backrest support, a nonlinear cushion model, a seat suspension model and a full vehicle model. Two kinds of road profiles – one with random roughness and one with a bump – have been used. It then compares the performance of five different seat suspension models based on a number of human comfort related parameters (seat to head transmissibility, suspension travel, seat acceleration, cushion contact force and head acceleration in both vertical and fore-aft directions) and vehicle handling parameters (vertical, rolling and pitching acceleration of chassis). The results clearly show the superiority of the configuration which involves a spring parallel to an inclined multi-stage damper. A separate analysis was also done to judge whether the integration of the vehicle model (with its associated complication) was necessary for this analysis. A comparison of the human body’s internal forces, moments, acceleration, and absorbed power with and without the vehicle model clearly indicates the need of using the former.


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