Mô phỏng lan truyền âm bằng phương pháp không lưới

NGHIEN CUrU - TRA O BO I

diing de lgc xi cho cac chi ti^t nhu: Than bom, ciit xa, gdi

do. Chat lugng be mat chi tiet sau diic dSu tdt hon so vdi

nhirng chi tiet diic khdng cd Igc xi. San phim Igc xi su

dung d Vien Cdng nghe diing de Igc xi cho chi tik la Puly

loai 6kg va loai 10kg. Chat lugng sau due b^ mat sach va

ldp da ddng deu.

5. Ketluan

Qua nghien cim thyc nghiem va so sanh ket qua thyc

nghiem vdi san pham nhap ngoai chiing tdi nit ra mdt sd

ket luan sau:

Nghien cim dugc cdng nghe che tao lgc xi xdp. San

pham da che tao dugc qua sir dung cho thay, cd the thay

the cho san pham nhap ngoai, mang lai y nghTa khoa hgc

va thyc tien cu the. Thdng qua ket qua tai cac ca sd due

trong nude cd the ap dyng che tao lgc xi xdp, gdp phan

tiet kiem ngoai te cho dat nude, tao viec lam va chii ddng

trong san xuat.

Thdng sd kT thuat co ban ciia lgc xi he SiC lien ket gdm

dat dugc tuong duong vdi san pham nhap ngoai ma gia

thanh chi bang 1/2.

Cac dieu kien can thiet de che tao Igc xi xdp nhu thiet

bj va vat tu deu san cd trong nude: Thiet bi nghien, thiet

bi khuay trdn, thiet bi nung..., xdp polyurethane nhap cua

Trung Qudc, san SiC, Zirconium silicate. Alumina hoat

tinh va cac phu gia tang cudng lien ket khdi... trong nude

khai thac dugc.Tuy nhien day la nhiing van de cdn mdi

nen can dugc nghien ciru sau va rdng hon ca ve ly thuy8t

va cdng nghe. Tir do nang cao them chat lugng de cd th8

mang lai hieu qua kinh te va ky thuat Idn hon. •

Tai lieu tham khao:

[1]. Olson III, R., Aubrey, L,. et al. Ceramic Foam Filter for

Better Filtration of Molten Iron. United States Patent Application

20060266714.2006.

[2]. Brown, J. R., Foseco Ferrous Foundryman's Handbook.

Butterworth-Heinemann, 2000.

[3]. Adier, J., Teichgraeber, M., et al. Open-cell expanded Ceramic

with a High Level of Strength, and Process for the Production. United

States Patent 6635339. 2003.

[4]. Brockmeyer, J., Aubrey, L., et al. Ceramic Foam Filter and

Process for Preparing. United States Patent 4885263. 1989.

[5]. Azumi, S. Ceramic Foam Filters. European Patent EP04I2673.

1990.

[6]. AdIer, J. Open-celled Silicon Carbide Foam Ceramic and Method

for Production thereof United States Patent 6887809. 2005.

[7]. Rice, R. Ceramic Fabrication Technology. Marcel Dekker, Inc.

2003

[8]. Pierson, H. Handbook of Refractory Carbides and Nitrides. Noyes

Publications. 1996.

MO PHONG LAN TRUYEN AM

BANG PHl/ONG PHAP KHdNG LlfCfl

(*) TRINH HC U TUAN

(**) NGUYEN THANH NHA

I.Mddau

Am hgc la nganh khoa hgc ve am

thanh, nghien ciru ve sy lan truyen

sdng am trong mdi trudng, sy tac ddng

ciia am len cau true, len thinh giac

con ngudi. Khai niem ve am thanh

khdng chi lien quan den thinh giac ma

cdn lien he den nhiing hien tugng lan

truyen dao ddng co hgc.

Am hgc la mdt nganh kha dac biet,

vi lien he kien thire vdi cac mdn hgc

khac nhu ca hgc chat ran, chat Idng, vat ly vat lieu, hoa

hgc, dien tir, kien true, am nhac, ngdn ngir hgc, tam ly

hgc, y hgc, sinh ly hoc,... Ngay nay, cac nghien cim ve

am hgc deu lien quan den viec phan tich, xir ly va kiem

soat tieng dn.

Cd nhieu phuang phap de giai quyet bai toan truyen

am. Khi may tinh chua phat trien, viec giai bai toan

truyen am chii yeu dya nhiing cdng thire giai tich. Tuy

nhien, ldi giai giai tich chi cd the cho ket qua tdt ddi vdi

Tom tat: Bai bao tap trung vao viec

giai phaong trlnh song Helmholtz bang

each ap dung phUOng phap khong chia

ludi "Element Free Galerkin (EFG)".

Chuong trinh tinh toan dUqfc xay dUng

dua tren ngdn ngiif Matlab, cac ket qua

tinh toan tU phuong phap khong lUcfi

duoc so sanh vofi ket qua giai tich va ket

qua tU chuong trinh Ansys (Phuong phap

Phan tur hufu han).

nhirng md hinh hai chieu don gian.

Vdi nhirng bai toan vdi phirc tap thi

ngudi ta chu yeu dya vao thuc nghiem

va phai chiu tdn kem.

Ngay nay, sy phat trien cua may

tinh va nhieu phuang phap tinh sd

da giup ich rat nhieu cho ngudi ky su

tinh toan. Ddi vdi bai toan truyen am,

theo tac gia hien nay tren the gidi co

hai phuong phap sd da dugc phat trien

va thuang mai hda thanh chuong trinh

md phdng. Dd la phuang phap phan ni

hiiu han (chuong trinh ANSYS) va phuong phap phan tu

bien (chuong trinh SYSNOISE).

Ben canh dd, hien nay cac phuong phap khdng chia

ludi da va dang dugc nghien ciru va phat trien de giai

quyet nhirng bai toan trong ky thuat. Cu the la cac bai toan

ca hgc vat ran bien dang, bai toan ddng lyc hgc luu chat

(*) Trung tam Khoa hpc KT thuat va Cong nghe Quan sir

(**) Tnrcmg Dai hpc Bach khoa TP.HCM

TAP CHf CO KHf V|| T NAM * So 03 - Thiing 03 nam 2010