Saving Weight from the ThyssenKrupp MULTI Rope-less Elevator System

26th June 2017 by Royston Jones

This post was written by my colleague, Biba Bedi, for the Altair Innovation Intelligence blog.

ThyssenKrupp, headquartered in Essen, Germany, launched its elevator system named MULTI last week. The company performed a live test of a full scale working prototype of the MULTI elevator in its specially built tower in Rottweil, Germany, which currently stands at a height of 244.10m.

As the world’s first rope-free elevator system, MULTI represents a technologically giant leap for the elevator industry. It does not require any roof mounted cables which enables it to travel with no limits in height like conventional elevators. Passengers therefore have no need to change elevators mid-journey. MULTI harnesses the power of linear motor technology, effectively moving multiple cars in a single shaft both horizontally and vertically, thus ending the need for elevators with ropes.

We collaborated with Thyssenkrupp Elevator on this project, using design optimization techniques to design material and weight out of the MULTI cabins.



With rapid urbanization and living space shrinking fast, cities are constantly expanding, buildings are growing skyward, faster. Greater mobility in taller buildings, and widening distances, with less wastage of space and time as people go about their lives, is becoming increasingly important to quality of life.

Conventional elevators are limited in the distance they can travel, requiring people to change cars to reach the higher floors on a skyscraper building. Recognizing the need for efficiency in this process, ThyssenKrupp Elevators wanted to develop an elevator which would allow them to move away from restrictive cable design and enable the elevators to move horizontally as well as vertically.

The new MULTI design concept presented its own challenges, chief among these being the fact that the system would not be able to carry as much weight as a traditional elevator. The new design had to be as lightweight as possible in order to maximize the loading capacity of the cabins.

Altair ProductDesign developed a multi-stage approach to redesign the supporting structure of the cabin to find a minimum mass solution that didn’t compromise on performance or safety. A topology optimization study was conducted using OptiStruct®, the design optimization solution within Altair’s HyperWorks suite.


Topology optimization study of MULTI’s supporting frame


New materials were explored to investigate the feasibility of using carbon fiber for the cabin’s walls. Altair ProductDesign developed an optimization study that would find not only the ideal thickness of the composite material, but also the ideal fiber ply shapes and lay-up orientation of each layer. These processes were applied to two concept designs created by ThyssenKrupp Elevator known as the ‘BackPack’ and the ‘SideGuide’, with the aim of providing insight into the best system to continue to develop.

The weight reduction project produced some impressive results. The concept optimization process on the BackPack structure, in combination with the sizing optimization of the sandwich panel walls, managed to produce a cabin that was 42% less than the target weight. If the walls were constructed from carbon fiber, it would be possible to go even further, down to 56% below target.