A model for investigating the influence of road surface texture and tyre tread pattern on rolling resistance

The reduction of rolling resistance is essential for a more environmentally friendly road transportation sector. Both tyre and road design can be utilised to reduce rolling resistance. In both cases a reliable simulation tool is needed which is able to quantify the influence of design parameters on the rolling resistance of a tyre rolling on a specific road surface. In this work a previously developed tyre/road interaction model is extended to account for different tread patterns and for losses due to small-scale tread deformation. Calculated contact forces and tyre vibrations for tyre/road interaction under steady-state rolling are used to predict rolling losses in the tyre. Rolling resistance is calculated for a series of different tyre/road combinations. Results are compared with rolling resistance measurements. The agreement between simulations and measurements is generally very good. It is found that both the tyre structure and small-scale tread deformations contribute to the rolling losses. The small-scale contribution depends mainly on the road roughness profile. The mean profile depth of the road surface is identified to correlate very well with the rolling resistance. Additional calculations are performed for non-traditional rubberised road surfaces, however, with mixed results. This possibly indicates the existence of additional loss mechanisms for these surfaces

Development of a Topics Course for Construction Law

The Cal Poly Construction Management program is designed to prepare students heading into the construction industry for daily management tasks. With construction comes many legal aspects integrated into a project’s operations. Though the curriculum includes a contract law course, a gap exists with a minimal number of classes that address the array of legal matters the construction industry must be versed in. Working with faculty member, Thomas Kommer, J.D., there is a need for a course that expands on these varying legal topics. In order to determine the specific topics that would impactfully benefit and educate Cal Poly Construction Management students, interviews were performed with both construction and legal professionals. Once the topics were established, literary reviews were performed to define the topics and benefits of adding this to our curriculum. This paper identifies the benefit from a topics course that dives deeper into construction law topics including real property law, professional licensing and insurance law, tort law with respect to negligence and willful conduct, labor law and employment law, and criminal law

Numerische Simulation von Rollgeräusch und Rollwiderstand von LKW-Antriebsachsenreifen

Bei LKWs wird im Allgemeinen zwischen Lenk-, Antrieb- und Zusatzachsen unterschieden. Die eingesetzten Reifen sind dabei im Gegensatz zu PKWs für die spezifischen Bedingungen an der jeweiligen Achse z.B. hinsichtlich Traktion, Abrieb, Sicherheit oder Wirtschaftlichkeit optimiert. Speziell im Regionalverkehr werden dabei aufgrund häufiger Beschleunigungs-/Bremsvorgänge und Kurvenfahrten an den Antriebsachsen Reifen mit ausgeprägtem Blockprofil verwendet. Die resultierende starke Schwingungsanregung führt selbst auf eigentlich geräuscharmen Straßenoberflächen unmittelbar zu einer erhöhten Geräuschemission. Aus diesem Grund ist die Entwicklung eines geräuscharmen Antriebsachsenreifens für den LKW-Regionalverkehr eines der Ziele des Verbundsprojektes "Leiser Stranßenverkehr 3" (LeiStra3). Zur Unterstützung dieses Vorhabens wurde ein existierendes numerisches Modell zur Berechnung von Reifen-/Fahrbahninteraktion, Rollgeräusch und Rollwiderstand für PKW-Reifen an die speziellen Erfordernisse der Simulation von LKW-Antriebsachsenreifen angepasst. Besonderer Augenmerk wurde dabei auf eine effiziente Abbildung des Querprofils und der resultierenden Reifenanregung gelegt. Neben der Geräuschemission wird als eine wichtige Kenngröße der Wirtschaftlichkeit auch der Rollwiderstand betrachtet um einen möglichen Zielkonflikt frühzeitig zu erkennen

The contribution of air-pumping to tyre/road noise

It is generally accepted that there are at least two tyre/road noise generation mechanisms commonly referred to as tyre vibrations and air-pumping. While the modelling of tyre vibrations is rather mature, the modelling of air-pumping is still on a basic stage and unsatisfactory in many aspects. Applying the fact that tyre vibrations and air-pumping have different vehicle speed dependency allows for identifying the contribution from each mechanism in field measurements of tyre/road noise. This paper presents an analysis of controlled pass-by measurements and simulations with the tyre/road simulation model at Chalmers. Results show that air-pumping is a major contributor to tyre/road noise. The question arises which physical mechanisms are behind the air-pumping noise observed in measurements and simulations. The analysis indicates that tyre vibrations in the contact may lead to air-pumping noise. This suggestion deviates from generation mechanisms usually assumed in the air-pumping context

A comparison between Finite Element and Waveguide Finite Element Methods for the simulation of tire/road interaction

Due to increasing road utilization and tightening regulations, an increasing effort is made by the tire and automotive industries for accurate modeling of tire/road noise. It is well known that finite element (FE) based methods describing the vibration response of a rolling tire are computationally expensive while analytical models do not offer the necessary accuracy in the structural description of the tire. The recently proposed waveguide finite element (WFE) method combines the detailed description of a discretized tire cross section with a computationally efficient wave approach in the circumferential direction. The method has been successfully applied for tire dynamics and rolling noise simulations. An important aspect for the modeling of rolling noise is an accurate description of the road induced excitation. Both the high frequency vibration field and the lower frequency or quasi-static contact area need to be accurately captured. In this work we compare FE and WFE models of a tire in terms of traditional NVH properties such as mobility and modal frequencies, and in term of contact behavior such as footprint shape and structural stiffness. This way the potential of the WFE method for the modeling of both the excitation and the response of a rolling tire is critically examined

Different strokes for different teams:the contingent effects of positive and negative feedback on the creativity of informationally homogeneous and diverse teams

Feedback is a ubiquitous management tool. Employing this tool to meet the new challenge of enhancing team creativity, raises the important question of whether positive or negative feedback is more effective. Unfortunately prior research on feedback valence and creativity is limited to the individual level, neglecting team creativity’s interdependent and knowledge-intensive nature. We address this issue and advance the team information processing perspective on team creativity by integrating two heretofore separate research streams to develop a team-specific model about how negative and positive feedback enhance creativity via two alternative information processing routes, contingent on teams’ informational diversity. Negative feedback fuels teams’ systematic effort and attention to external, novel information. In informationally diverse teams, in which members hold different information and perspectives, these efforts promote team creativity through information elaboration. Conversely, positive feedback propels members to flexibly use their information and contribute the resultant divergent insights to the team. In informationally homogeneous teams, where these insights relate to others’ information and perspectives, these divergent insights trigger teams’ generative processing and in turn creativity. Results from a team experiment support the predicted feedback valence by informational diversity interaction on team creativity through elaboration and generative processing

Diversity and Creativity

Hoever’s dissertation investigates the conditions and processes that enable teams to develop more creative solutions and optimally use their informational resources for higher creativity. Whereas teams, especially those composed of members with different task-relevant information and perspectives, are considered a particularly viable means to the end of higher creativity, systematic research on the factors that facilitate team creativity and the processes conducive to it is sparse and its findings remain fragmented to date. The three empirical studies included in this dissertation contribute to a more complete understanding of how teams achieve creative outcomes by addressing different aspects of this question. Hoever’s findings highlight that other-focused behaviours such as perspective taking and mutual feedback between team members represent important mechanisms to bring out the potential of team diversity for team creativity. Furthermore, on the basis of an in-depth behavioural observation of the teams throughout their creative process, she was able to develop a more nuanced understanding of the processes that underlie these observed effects. This analysis yields converging evidence for the importance of information elaboration as a precursor of higher creativity in diverse teams but not for other processes frequently suggested to transmit the benefits of diversity when they occur. Finally, the reported research points to the differential impact of formal external interventions in shaping team processes and information processing mechanisms in teams with diverse informational resources. Together, the reported research has important implications for future work on team creativity, diversity, and team processes. With regards to team creativity and diversity the results call into question the straightforward nature of the frequently proposed link between diversity and creativity and highlight a number of important moderators of this effect. Moreover, the findings indicate that the relationship between creativity and its antecedents at the team level do not fully mirror the effects observed at the individual level of analysis. Finally, they direct attention to the need to systematically investigate the extent to which diverse and homogeneous teams react differently to common managerial interventions such as feedback