Dr.-Ing. Dipl.-Wirt.-Ing. Christoph Löpenhaus

Dr. -Ing. Dipl. -Wirt. -Ing. Christoph Löpenhaus has since 2014 served as Chief Engineer in the Gear Department of WZL, RWTH Aachen / Laboratory of Machine Tools and Production Engineering (WZL), RWTH Aachen. He previously held positions there as (2011-2014) Team Leader, Group Gear Testing Gear Department Chair of Machine Tools Laboratory of Machine Tools and Production Engineering (WZL) RWTH Aachen; (2010-2011) Research Assistant, Group Gear Testing Gear Department Chair of Machine Tools Laboratory of Machine Tools and Production Engineering (WZL) RWTH Aachen: (2007-2009) as Student Researcher, Group Gear Design and Manufacturing Calculation Gear Department Chair of Machine Tools Laboratory of Machine Tools and Production Engineering (WZL) RWTH Aachen; and (2004-2009) as a student in Industrial Engineering RWTH Aachen. (Bio last updated 2018-02-05 Contact Randy Stott, Managing Editor, with changes.)

Articles by Christoph Löpenhaus

  • Analysis of the Influence of the Working Angles on the Tool Wear in Gear Hobbing (January/February 2018)
    A calculation method is developed to estimate tool wear on hobs.
  • Influence of the Defect Size on the Tooth Root Load Carrying Capacity (November/December 2017)
    The objective of this work is to introduce a method for the calculation of the tooth root load carrying capacity for gears, under consideration of the influence of the defect size on the endurance fatigue strength of the tooth root. The theoretical basis of this method is presented in this paper as well as the validation in running tests of helical and beveloid gears with different material batches, regarding the size distribution of inclusions. The torque level for a 50 percent failure probability of the gears is evaluated on the test rig and then compared to the results of the simulation. The simulative method allows for a performance of the staircase method that is usually performed physically in the back-to-back tests for endurance strength, as the statistical influence of the material properties is considered in the calculation model. The comparison between simulation and tests shows a high level of accordance.
  • Analysis of Excitation Behavior of Two-Stage Gearbox Based Upon Validated Simulation Model (September/October 2017)
    In order to reduce costs for development and production, the objective in gearbox development and design is to predict running and noise behavior of a gearbox without manufacturing a prototype and running expensive experimental investigations. To achieve this objective, powerful simulation models have to be set up in a first step. Afterwards, those models have to be qualified and compared to experimental investigations. During the investigation procedure of gearboxes, there are two possibilities to evaluate the running and noise behavior: quasi-static and dynamic investigations. In times of engine downsizing, e-mobility and lightweight design, the dynamic excitation behavior is becoming increasingly important.
  • FE-Based Approaches for Tip Relief Design (August 2017)
    The deformation of the gear teeth due to load conditions may cause premature tooth meshing. This irregular tooth contact causes increased stress on the tooth flank. These adverse effects can be avoided by using defined flank modifications, designed by means of FE-based tooth contact analysis.
  • Surface Characteristics of Hobbed Gears (July 2017)
    Gear hobbing is one of the most productive manufacturing processes for cylindrical gears. The quality of the gears is a result of the tool quality, the precision of the workpiece, tool clamping and kinematics of the machine. The dry gear hobbing process allows machining of gears with a quality according to the DIN standard up to IT 5. To evaluate which gear quality is possible to machine with a given clamping and hob, it is useful to simulate the process in advance.
  • Inclusion-Based Bending Strength Calculation of Gears (May 2017)
    Reduced component weight and ever-increasing power density require a gear design on the border area of material capacity. In order to exploit the potential offered by modern construction materials, calculation methods for component strength must rely on a deeper understanding of fracture and material mechanics in contrast to empirical-analytical approaches.
  • Performance of Gears Manufactured by 5-Axis Milling (March/April 2017)
    Free form milling of gears becomes more and more important as a flexible machining process for gears. Reasons for that are high degrees of freedom as the usage of universal tool geometry and machine tools is possible. This allows flexible machining of various gear types and sizes with one manufacturing system. This paper deals with manufacturing, quality and performance of gears made by free form milling. The focus is set on specific process properties of the parts. The potential of free form milling is investigated in cutting tests of a common standard gear. The component properties are analyzed and flank load-carrying capacity of the gears is derived by running trials on back-to-back test benches. Hereby the characteristics of gears made by free form milling and capability in comparison with conventionally manufactured gears will be shown.
  • Influence of Topography Deviations on the Psychoacoustic Evaluation of Ground Bevel Gears (November/December 2016)
    In the design process of transmissions, one major criterion is the resulting noise emission of the powertrain due to gear excitation. Within the past years, much investigation has shown that the noise emission can be attributed to quasi-static transmission error. Therefore, the transmission error can be used for a tooth contact analysis in the design process, as well as a characteristic value for quality assurance by experimental inspections.