VOTO

Fig­ure 1: VO­TO ma­te­rial - wil­low fab­ric-re­in­forced plas­tic / wood-tex­tile com­posite (WTC)

As part of the VO­TO pro­ject “Wil­low fab­ric-re­in­forced plas­tic with vari­able fab­ric den­si­ty in tex­tile tim­ber con­struc­tion”, façade mo­d­ules made of fab­rics made of wil­low wood threads and po­lypropy­lene were de­vel­oped for use in tex­tile tim­ber con­struc­tion (Fig­ure 1). To this end, the equip­ment for the lab­o­ra­to­ry-scale pro­duc­tion of cont­in­u­ous fil­a­ments from wil­low rails and a lab­o­ra­to­ry loom (Fig­ure 2, left) were ini­tial­ly fur­ther de­vel­oped for the pro­duc­tion of wo­ven fab­rics. This was used to pro­duce test spec­i­men variants for studies for the de­sign work for two planned de­mon­s­tra­tor façades on the cam­pus and the ex­ten­sive ma­te­rial char­ac­ter­i­za­tion. At the same time, vari­ous in­vesti­ga­tions were car­ried out to op­ti­mize the pro­cess, from which the op­ti­mized pro­cess con­di­tions for the pro­duc­tion of the façade mo­d­ules in the hot com­pact­ing pro­cess could be suc­cess­ful­ly de­rived. In par­tic­u­lar, the pa­ram­e­ters of pres­sure, time and tem­per­a­ture were tak­en in­to ac­count in or­der to achieve the least pos­si­ble da­m­age to the wil­low fab­ric dur­ing the pro­cess. Evi­dence was pro­vid­ed by means of mi­cros­copy and CT im­ages, as well as a chem­i­cal anal­y­sis of the wood. Fig­ure 2 (right) shows the op­ti­mized stan­dard struc­ture of the wil­low fab­ric-re­in­forced plas­tics (wood-tex­tile com­posites, WTC for short).

Fig­ure 2: left: Pro­duc­tion of wil­low wood fab­rics on the adapt­ed lab­o­ra­to­ry shaft loom; right: the fin­ished wil­low fab­ric-re­in­forced plas­tic (WTC)

Fur­ther­more, the re­sult­ing com­posite ma­te­rial was ex­amined with re­gard to its quasi-stat­ic, cyclic-dy­nam­ic and dy­nam­ic-im­pact prop­er­ties. In de­tail, ten­sile, com­pres­sion and 3-point bend­ing tests were car­ried out and the prop­er­ties were de­ter­mined in the punc­ture, im­pact and im­pact bend­ing tests. The ten­sile tests were al­so sup­port­ed by dig­i­tal im­age cor­re­la­tion and sup­ple­ment­ed by fa­tigue tests. In ad­di­tion, per­fo­ra­tion tests were car­ried out against the back­ground of a ne­ces­sary fas­ten­ing. Due to the planned out­door use, ar­ti­fi­cial weather­ing of the ma­te­rial was al­so car­ried out and its ef­fects on the me­chan­i­cal prop­er­ties an­a­lyzed. Based on the re­sults ob­tained dur­ing the weather­ing, the PP ma­trix was ad­di­ti­vat­ed with UV sta­bi­l­iz­ers and flame re­tar­dants and their im­pact on the me­chan­i­cal prop­er­ties was test­ed. The flamma­bil­i­ty of the ma­te­rial was al­so an­a­lyzed. An ex­cerpt of the tests car­ried out is shown in Fig­ure 3.

Fig­ure 3: Test­ing of WTC

It was shown that the de­vel­oped com­posites have good me­chan­i­cal prop­er­ties, which are com­para­ble to those of clas­sic na­t­u­ral fiber-re­in­forced ther­mo­plas­tics.

The weather­ing sta­bil­i­ty was im­proved by the use of UV sta­bi­l­iz­ers and the burn­ing rate was re­duced by the use of the flame re­tar­dant. The re­sults flowed in­to an ex­ten­sive de­sign pro­cess for the de­mon­s­tra­tor façades, so that at the end of the pro­ject an opaque and a trans­lu­cent façade de­sign were de­vel­oped and im­ple­ment­ed (Fig­ure 4).

Fig­ure 4: Opaque and trans­lu­cent façade mo­d­ule (top), façade de­sign (bot­tom left), woo­d­en mesh (bot­tom cen­ter) press­ing tool (bot­tom right)

Par­al­lel to the pro­ject, a spe­c­i­fi­ca­tion sheet was drawn up, which can serve as a tem­plate for fu­ture in­dus­trial im­ple­men­ta­tion and can be found in the ap­pendix to the fi­nal re­port.

Ac­knowl­edge­ments: The IGF pro­ject 21712 N of the Forschungsvereini­gung Werk­stoffe aus nach­halti­gen Roh­stof­fen e. V. (WNR) and the Forschungsku­ra­to­ri­um Tex­til e. V. (FKT) was fund­ed via the AiF as part of the pro­gram for the pro­mo­tion of joint in­dus­trial re­search (IGF) by the Fed­er­al Min­istry of Eco­nomics and Cli­mate Pro­tec­tion (BMWK) on the ba­sis of a re­s­o­lu­tion of the Ger­man Bun­des­tag. We would like to thank them for their sup­port. We would al­so like to thank the mem­bers of the pro­ject ad­vi­so­ry com­mit­tee for their sup­port.