Investigation of alternative approaches for load recovery on a truck chassis using indirect measurements

Jacobs, Eugene (2020-03)

Thesis (MEng)--Stellenbosch University, 2020.

Thesis

ENGLISH ABSTRACT: A proper description of the input loading experienced by a truck during operation is essential. This makes it possible to perform high quality finite element analysis which can validate designs numerically, rather than via physical prototype testing. Higher quality finite element analysis will lead to safer vehicle designs for drivers and the general public. Less time spent on prototyping would lead to faster releases of new designs into the market, preserving both time and money for manufacturers. The feasibility of alternative approaches for load recovery on a truck chassis using indirect measurements was investigated in this thesis. The first approach utilised acceleration measurements processed with multi-body dynamic simulations. The second approach utilised the linear relationship between strain and input loading and superposition to recover said input loading. Strain gauges were used as measurement instruments for this approach. Both approaches have advantages and disadvantages. Investigation of various influencing factors on both approaches led to the conclusion that load recovery, using acceleration data and a simple quarter truck model, produces load recoveries with sufficient accuracy. This approach is also the least computationally complex, is relatively easy to set up and is a low-cost alternative to direct measuring methods which use expensive force transducers instrumented in the load path. Furthermore, this approach does not alter the truck in any way, aside from the instrumentation of accelerometers at key locations on the truck chassis and wheels.

AFRIKAANSE OPSOMMING: Die behoorlike beskrywing van die insetlading wat 'n vragmotor ondervind, is noodsaaklik om eindige elementanalises van hoë gehalte uit te voer. Hierdie eindige elementanalises bevestig ontwerpe numeries, eerder as om van fisiese prototipe-toetsing gebruik te maak. Eindige elementanalises van hoër gehalte sal lei tot veiliger voertuigontwerp vir bestuurders en die publiek. Minder tyd sal aan prototipe toetsing bestee word, wat sal lei tot vinniger vrystelling van nuwe ontwerpe aan die mark, wat die vervaardiger tyd en geld bespaar. Die haalbaarheid van alternatiewe metodes tot die benadering van die insetlading wat vragmotor-onderstel ervaar met indirekte metings was ondersoek in hierdie tesis. Die eerste benadering maak gebruik van versnellingsmetings, wat met versnellingsmeters gemeet was, en verwerk met dinamiese veel liggaam simulasies. Die tweede benadering het gebruik gemaak van die lineêre verband tussen spanning en insetbelasting om genoemde insetlading te herstel. Rekstrokies was as meetinstrument vir hierdie benadering gebruik. Beide benaderings het voor- en nadele. Na die ondersoek van verskillende beïnvloedingsfaktore op albei benaderings, was gevolgtrekkings gemaak dat akkurate vragherwinning met behulp van versnellingsdata en 'n eenvoudige model van 'n kwart vragmotor verkrybaar was. Hierdie benadering is ook die minste berekeningkompleks en relatief maklik om op te stel. Verder verander die benadering die vragmotor op geen enkele manier nie, behalwe vir die instrumentasie van versnellingsmeters op sleutelplekke op die vragmotor-onderstel en wiele. Die metode is 'n laekoste-alternatief vir direkte meting metodes wat gebruik maak van duur lasomsetters wat op die trok se wielle geïnstalleer moet word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/108219
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