Perbaikan Sistem Kerja Proses Pemasangan Ban Truk dengan Perancangan Peralatan Pendukung Menggunakan QFD dan REBA

PT.X as one of the heavy equipment manufacturing company are producing mining and non-mining transportation product (e.g. Semi Side Tipper (SST) & Dolly). In producing those kinds of products that mostly using tires, there is a process area to do mounting truck tire. Based on interviews and direct observation results, there is a symptom of Cumulative Trauma Disorders (CTD), especially in the low back area. The low back pain experienced by the operators is caused by an awkward posture that resulted from Manual Material Handling (MMH) in this process. Lifting and holding the tire that is located on the floor with diameter 1.2m, height 0.3m, and weight 90 Kg also the reasons why the awkward posture appears during the mounting truck tire process. Using Rapid Entire Body Assessment (REBA), Nordic Questionnaire, and followed by the Quality Function Deployment (QFD) approach for product design are used to do the improvement for the process. In the end, these ergonomics issues are solved by developing material handling tools that can minimize the risk and symptoms of CTDs. It can be shown by initially REBA score is on level 11 (Very High Risk) to level 7 (Medium Risk) and for the Nordic result from 7 body parts that feel discomfort, now it just becomes 1 body parts feel discomfort.

Thermomechanical Coupling of a Hyper-viscoelastic Truck Tire and a Pavement Layer and its Impact on Three-dimensional Contact Stresses

A thermomechanical coupling between a hyper-viscoelastic tire and a representative pavement layer was conducted to assess the effect of various temperature profiles on the mechanical behavior of a rolling truck tire. The two deformable bodies, namely the tire and pavement layer, were subjected to steady-state-uniform and non-uniform temperature profiles to identify the significance of considering temperature as a variable in contact-stress prediction. A myriad of ambient, internal air, and pavement-surface conditions were simulated, along with combinations of applied tire load, tire-inflation pressure, and traveling speed. Analogous to winter, the low temperature profiles induced a smaller tire-pavement contact area that resulted in stress localization. On the other hand, under high temperature conditions during the summer, higher tire deformation resulted in lower contact-stress magnitudes owing to an increase in the tire-pavement contact area. In both conditions, vertical and longitudinal contact stresses are impacted, while transverse contact stresses are relatively less affected. This behavior, however, may change under a non-free-rolling condition, such as braking, accelerating, and cornering. By incorporating temperature into the tire-pavement interaction model, changes in the magnitude and distribution of the three-dimensional contact stresses were manifested. This would have a direct implication on the rolling resistance and near-surface behavior of flexible pavements.

Relationship between Tire Ground Characteristics and Vibration Noise

To study the relationship between tire ground characteristic parameters and vibration noise, a radial truck tire (295/80R22.5) is selected as the research object, and a finite element model is established. The test results of the tire stiffness, vibration modal, and surface velocity response are used to verify the model. In order to find the influence of the inherent vibration characteristics of a tire on radiated noise, the contour design and belt design are selected as design schemes, and a modal analysis and vibration noise numerical simulation analysis are carried out for different tire structures. The footprints of the tire-ground are refined and divided. All the grounding parameters of each subarea are extracted, and the relationships between the geometric and mechanical parameters of the tire ground characteristics and vibration noise are investigated. Then, the effects of the skewness and stiffness of tread deformation, as well as the spectral density of tire–road excitation force power on vibration noise, are analysed. The results showed that a positive correlation exists between the vibration noise and the skewness of the tread radial deformation; however, a negative correlation is observed between the vibration noise and radial deformation stiffness. The peak values and numbers of the tire excitation force power spectral density using the minimum noise structure design are significantly smaller than those of the original tire. This study can serve as a theoretical guideline for the structural design of low-noise tires.