Wire Ropes in Crane Applications – Current State of the Standardization Work of ISO/WD 16625

Judith Reinl,Markus Golder

doi:10.14464/innotrac.v1i0.456

Abstract

Nowadays, modern standards apply the proof of competence method to prove that a design force does not exceed a certain limit to ensure a certain safety level. Furthermore, standards elaborated during the last years apply a cycle-based approach instead of a time-based approach. The shortcomings of the standard ISO 16625:2013 need to be addressed in a revision. Therefore, a working group WG3 of ISO/TC 96 SC3 has been established in 2015 to prepare a new working draft ISO/WD 16625. Objectives are to adopt a cycle-based approach and to incorporate proofs of competence for static strength and fatigue strength for running ropes and stationary ropes, based on scientific inputs. The research work about steel wire ropes by the University of Stuttgart and the Technical University of Dresden developed the method Stuttgart and the method Leipzig, both representing regression models to determine the attainable number of bending cycles of a wire rope. The present paper briefly explains the method Leipzig and the method Stuttgart in chapter 3. In chapter 4, the partly implementation of findings from the method Stuttgart to the standard EN 13001-3-2:2014 is discussed and shortcomings are identified. Those shortcomings have also been addressed by the new developed concept of ISO/WD 16625 that is outlined in chapter 5. Finally, chapter 6 provides an overview on the revised ISO/WD 16625 to conclude the current state of the standardization work.

Highlights

IntroductionThe international standard ISO 16625 Cranes and hoists – Selection of wire ropes, drums and sheaves, valid in its first edition from 2013, specifies a minimum design factor Zp taking mainly into account the classification of mechanism, the rope type and the application. [1] In ISO 16625:2013, the group classification of mechanism is in accordance with ISO 4301-1:1986 and follows a time-based approach. [2] Considering the maximum rope tension S and selecting a specified value of the minimum design factor Zp, the minimum breaking force of the rope Fmin is determined by a simple calculation [1]: Fmin ≥ S × ZpReinl and Golder / innoTRAC Journal 1 (2020)Nowadays, modern standards apply the proof of competence method to prove that a design force does not exceed a certain limit to ensure a certain safety level
Modern standards apply the proof of competence method to prove that a design force does not exceed a certain limit to ensure a certain safety level
The stated objectives of a revision of ISO 16625 have been met the standardization work for stationary ropes at the time of this publication is not yet finalized

Summary

Introduction

The international standard ISO 16625 Cranes and hoists – Selection of wire ropes, drums and sheaves, valid in its first edition from 2013, specifies a minimum design factor Zp taking mainly into account the classification of mechanism, the rope type and the application. [1] In ISO 16625:2013, the group classification of mechanism is in accordance with ISO 4301-1:1986 and follows a time-based approach. [2] Considering the maximum rope tension S and selecting a specified value of the minimum design factor Zp, the minimum breaking force of the rope Fmin is determined by a simple calculation [1]: Fmin ≥ S × ZpReinl and Golder / innoTRAC Journal 1 (2020)Nowadays, modern standards apply the proof of competence method to prove that a design force does not exceed a certain limit to ensure a certain safety level. The international standard ISO 16625 Cranes and hoists – Selection of wire ropes, drums and sheaves, valid in its first edition from 2013, specifies a minimum design factor Zp taking mainly into account the classification of mechanism, the rope type and the application. [2] Considering the maximum rope tension S and selecting a specified value of the minimum design factor Zp, the minimum breaking force of the rope Fmin is determined by a simple calculation [1]: Fmin ≥ S × Zp. Reinl and Golder / innoTRAC Journal 1 (2020). The shortcomings of ISO 16625:2013 are obvious: a time-based approach, i.e. the total duration of use, of the classification of mechanism forms the foundation to select a minimum design factor Zp components of a mechanism are worn by stress cycles.

Objectives

Methods

Conclusion