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Materials Science in Additive Manufacturing TPMS for perfect sound absorption

A

B

C

Figure 5. Triply periodic minimal surface (TPMS) structures manufactured by laser powder bed fusion (LPBF): (A) Uniform TPMS, (B) graded primitive,
and (C) multicavity TPMS

k = k ' − jk '' (Ⅶ) the rigid baffle structure at the bottom of the multicavity
structure, adjusting the distance between the tail cavity has
The test method for Bloch wave vector q is described as little effect on the overall impedance value of the structure,
follows. The TPMS structure was placed in the impedance making it difficult to determine the true wavenumber
tube, ensuring that the end face was flush with the inner frequency graph of the multicavity structure. Therefore,
end face of the tube. Assuming a rigid scale of 30 mm, this measurement is only effective for structures without
the cavity was extended from 10 to 40 mm for sound rigid walls and is invalid for multicavity structures.
absorption testing, and the sound impedance file was
saved. Next, the cavity was extended from 40 to 50 mm, 3. Results and discussion
creating a cavity length of 20 mm; sound absorption testing 3.1. Sound absorption characteristics of multicavity
was performed again, and the acoustic impedance file
was saved accordingly. Finally, the two distance acoustic without TPMS
impedance files were imported, and the Bloch wave vector The sound absorption coefficient curves of the multicavity
k of the acoustic metamaterial was calculated. Due to structure with four depths, including 12, 18, 24, and

Volume 4 Issue 1 (2025) 7 doi: 10.36922/msam.5737