Title:
Material Behavior of an Ultra-High-Performance Concrete Forming Die for Sheet Metal Hydroforming
Author(s):
Robert Ritter, Manfred Curbach, Michael Trompeter, and A. Erman Tekkaya
Publication:
Materials Journal
Volume:
106
Issue:
6
Appears on pages(s):
515-522
Keywords:
confinement; multiaxial stress state; sheet metal hydroforming; stress-strain behavior; ultra-high-performance concrete; uniaxial stress state
DOI:
10.14359/51663334
Date:
11/1/2009
Abstract:
Economic requirements and an increasing number of part variants have led to the development of new sheet metal forming techniques and low cost forming dies. For sheet metal hydroforming, these dies have to withstand pressures of approximately 100 MPa (14.50 ksi) to form detailed and uniform sheet metal contours in the range of elastic material behavior of the die material. A promising approach to make the production of dies cost-efficient is the use of ultra-high-performance concrete (UHPC), particularly for high-pressure sheet metal hydroforming. The stress-strain behavior for uniaxial and triaxial compressive stress states was investigated experimentally for a fine grained UHPC at various ages. Additionally, three confinements of concrete cylinders were tested to achieve a multiaxial stress state. A forming tool prototype was fabricated and its performance applying a fluid pressure up to 90 MPa (13.05 ksi) was analyzed. The shape accuracy of the formed sheets and the ultimate load of the prototype were examined. Also, the friction coefficient between sheet metal and concrete was determined. The forming tests have approved that the investigated UHPC can be successfully used as die material for sheet metal hydroforming.