On the design of Len Lye’s harmonic sculptures at the largest feasible size

Abstract

“I don’t expect to see this sort of thing done in my lifetime, but the directions are there and when we’re ready to get around to it – go ahead. Don’t let me stop you!”-Len Lye [3]

Len Lye (1901 - 1980), born in Christchurch, New Zealand, was a pioneering artist whose work spanned a wide array of media. He is best known for his kinetic sculptures which were first exhibited in New York in the 1960’s. Over the last 20 years, the University of Canterbury has participated in the engineering design and construction of a number of Lye’s most ambitious sculptures, notably Big Blade (New Plymouth) [4], and Water Whirler (Wellington) [5]. Investigatory and prototype work into the sculptures Giant Blade [6] and Sun, Land and Sea [7] brings these visions closer to reality.

The Len Lye Foundation, an organisation tasked with promoting and preserving Lye’s artworks posthumously, approached the department of Mechanical Engineering at the University of Canterbury with an initiative to produce ten new works over the next ten years. As part of this project external to the University, Waving Wands [8], has been installed on the New Plymouth Coastline, and a larger version of Witch Dance [9] was unveiled in early 2019, titled Wand Dance [10].

This thesis is presented to expedite the production of several of Len Lye’s sculptures featuring similar mathematical models, owing to shared vibratory forms and choreography in their artistic performances. Owing to generous funding from the Gibb’s Foundation to support the Len Lye Foundation’s efforts, part of this thesis focuses on the development of one particular new work titled Flaming Harmonic. However, Flaming Harmonic is not an isolated artwork, and developing Flaming Harmonic yields design processes and information relevant to a family of artworks, titled as Lye’s Harmonic sculptures.

Four Harmonic sculptures in particular are discussed: Flaming Harmonic, Water Whirler, Zebra, and Rotating Harmonic. These artworks have choreographed performances which feature a vibratory form based on the bending modes of a cantilevered beam. As a performance plays, the cantilever may vibrate to produce a two- or three-dimensional form when an artwork is oscillated near a resonant frequency.

Producing these works requires understanding the artists’ design philosophy and intentions for the works, especially as many of Lye’s works were left behind as notes and drawings for the Len Lye Foundation. Often, Lye desired versions of his artworks produced at many times their original scale, from gallery versions of one or two metres, to filling giant sculpture parks “the modern equivalent of ancient monuments such as Stonehenge or the great pyramids” [11].

Harmonic sculptures require large amplitude vibrations as part of their artistic performances, and this has led to premature failure of the vertical cantilevers under fatigue loading conditions. The response from the Len Lye Foundation is a desire to improve upon Lye’s original mechanisms and optimise the design of these flexible cantilevers, called wands, which are central to each artistic performance.

At the Len Lye Foundations request, the primary aim of this thesis is to enable Harmonic sculptures to be realised at the maximum possible scale.

We start by investigating the artist’s method for producing Harmonic artworks, and use these to ensure the artistic intent is preserved when increasing the size of an artwork. Then, we examine the additional performance elements required to produce a full-size version of Flaming Harmonic – notably the emission of jets of water or fire from jets located along the flexible wand.

This study follows previous investigations into Lye’s work using non-dimensional representations of Lye’s artworks, to investigate the influence of size on structural parameters of vertical cantilevers [4]. Preserving the artistic intent requires maintaining static similarity between original and scaled geometries, by holding the influence of gravity to flexural rigidity as a constant. Here, scaling requirements are extended for tubular and fluid filled geometries, then used to predict approximate limits on the scalability of Harmonic artworks.

Previous authors have indicated that altering the clamping geometry might improve the scalability of Harmonic artworks. Here, two promising alternative clamping arrangements are investigated to determine how, and if, these arrangements are capable of reducing stresses, while producing artistically acceptable performances.

This study uses a closed form free-vibrations model of a beam subject to gravitationally induced axial tension from the literature [12]. Through the use of Greens functions, a support along the beam is enforced to simulate the two alternative clamping arrangements. Predictions for how these arrangements alter stress, frequency, and artistic suitability are presented for a range of non- dimensionalised cantilevers. The gravitational influence is varied, to characterise the solution space surrounding the use of these clamping arrangements as they relate to Harmonic sculptures.

Next, we detail the engineering process required to produce optimal designs for wands undergoing large amplitude flexure. This wand design process combines the presented scaling and clamping geometry analyses, and assesses factors including material selection and composite layup to produce simultaneously strong and flexible beams.

This study develops optimisation criteria to select a material which best meets the structural demands of the work, and the design requirements specific to Harmonic sculptures. Following the selection of a composite material, a method for producing an optimum layup using classical lamination theory and the scaling requirements we developed is presented. The wand design process is applied to Flaming Harmonic to generate geometric specifications and predict operating loads for a 10m tall version of the artwork, intended for use with a proposed alternative clamping geometry.

A conceptual-to-detail level design of a drive mechanism and supporting structures for the 10m tall Flaming Harmonic is presented, to facilitate production of this artwork on request. It is intended that this design may be modified to accommodate a range of Harmonic sculptures as required.

Part way through this project Len Lye’s Water Whirler sculpture, which features prominently on the Wellington waterfront was vandalised. This caused damage to the wand and drive mechanism of the artwork. A new wand and repairs to the drive machinery were required to restore the sculpture.

This study involved developing a numerical model of the coupled wand and drive mechanism of Water Whirler. Following a simulation of the previous artwork, the scaling requirements were adapted to generate geometric specifications for a replacement Water Whirler wand following the wand design process. Using the numerical model, operating loads for the new wand were predicted. Using the finished design specifications, the replacement wand was fabricated and installed in Wellington in June 2019.

The research outcomes of this thesis have so far seen the Water Whirler sculpture be re-commissioned, and presented plans to the Gibb’s foundation for a 10m tall version of Flaming Harmonic.

This work is readily extendible to new versions of several Len Lye sculptures using the adaptable machine design plans, and optimised wand design process included. It is hoped this thesis may keep Lye’s impressive visions firmly in the domain of the 21st century, and that new versions of Harmonic sculptures will be built following this thesis.