Panel kayu Penentuan modulus elastisitas lentur dan keteguhan lentur

SNI ISO 16978:2010

Standar Nasional Indonesia

Wood-based panels – Determination of modulus elasticity in bending and of bending strength (ISO 16978: 2003, IDT)

ICS 79.060

Badan Standardisasi Nasional

” Copy SNI ini dibuat oleh BSN untuk Panitia Teknis 79-01 Hasil Hutan Kayu “

Panel kayu – Penentuan modulus elastisitas lentur dan keteguhan lentur


© BSN 2010 Hak cipta dilindungi undang-undang. Dilarang menyalin atau menggandakan sebagian atau seluruh isi dokumen ini dengan cara dan dalam bentuk apapun dan dilarang mendistribusikan dokumen ini baik secara elektronik maupun tercetak tanpa izin tertulis dari BSN BSN Gd. Manggala Wanabakti Blok IV, Lt. 3,4,7,10. Telp. +6221-5747043 Fax. +6221-5747045 Email: [email protected] www.bsn.go.id Diterbitkan di Jakarta

SNI ISO 16978:2010

Daftar Isi

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Daftar Isi ....................................................................................................................................i Prakata .................................................................................................................................... iii 1 Ruang lingkup.................................................................................................................... 1 2 Acuan normatif................................................................................................................... 1 3 Prinsip................................................................................................................................ 1 4 Alat..................................................................................................................................... 1 5 Contoh uji........................................................................................................................... 3 6 Prosedur ............................................................................................................................ 5 7 Pernyataan hasil ................................................................................................................ 7 8 Laporan hasil ....................................................................................................................... 9

SNI ISO 16978:2010

Table of content

© BSN 2010

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Table of content ........................................................................................................................ii 1 Scope................................................................................................................................... 2 2 Normative references........................................................................................................... 2 3 Principle ............................................................................................................................... 2 4 Apparatus ............................................................................................................................ 2 5 Test pieces .......................................................................................................................... 4 6 Procedure ............................................................................................................................ 6 7 Expression of results ........................................................................................................... 8 8 Test report ......................................................................................................................... 10

SNI ISO 16978:2010

Prakata

Standar Nasional Indonesia (SNI) ISO 16978:2010, Panel kayu – Penentuan modulus elastisitas lentur dan keteguhan lentur ini merupakan hasil adopsi identik dengan metode terjemahan dari ISO 16978-2003, Wood-based panels – Determination of modulus elasticity in bending and of bending strength. Alasan adopsi standar ini adalah harmonisasi standar dan kebutuhan di lapangan. Apabila terdapat keraguan dalam standar ini, maka mengacu standar aslinya.

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Standar ini disusun oleh Panitia Teknis 79-01 Hasil hutan kayu. Standar ini telah dibahas dalam rapat teknis dan disepakati dalam rapat konsensus pada tanggal 18 – 20 November 2010 di Bogor.


© BSN 2010

SNI ISO 16978:2010

Panel kayu – Penentuan modulus elastisitas lentur dan keteguhan lentur

1

Ruang lingkup

Standar ini menetapkan metode penentuan modulus elastisitas lentur dan keteguhan lentur panel kayu dalam dalam posisi rebah (flatwise bending).

2

Acuan normatif

ISO 9424, Wood-based panels – Determination of dimensions of test pieces ISO 16999, Wood-based panels – Sampling and cutting of test pieces

3

Prinsip

Modulus elastisitas lentur dan keteguhan lentur ditentukan dengan pembebanan terpusat di tengah contoh uji yang disangga pada dua titik. Modulus elastisitas dihitung menggunakan kemiringan garis linier pada kurva beban-defleksi; nilai yang didapat merupakan modulus apparent, bukan modulus nyata, karena dalam metode uji ini terdapat geseran seperti halnya pada uji lentur. Keteguhan lentur tiap contoh uji dihitung dengan menentukan rasio momen lentur/bending moment M, pada saat beban maksimum Fmax, terhadap momen pada penampang lintang penuh.

4

Alat

4.1

Alat pengukuran, sesuai ISO 9424.

4.2

Alat uji, memiliki komponen-komponen penting seperti (lihat Gambar 1):

4.2.1 Dua buah roller penyangga silindris yang sejajar satu dengan yang lain, dengan panjang lebih dari lebar contoh uji, diameter (10±0,5) mm (untuk panel dengan ketebalan ≤ 6 mm) dan diameter (15±0,5) mm (untuk panel dengan ketebalan > 6 mm). Jarak antar penyangga dapat disesuaikan. 4.2.2 Kepala beban silindris, dengan panjang lebih dari lebar contoh uji, dan diameter (10±0,5) mm (untuk panel dengan ketebalan ≤ 6 mm) dan diameter (30±0,5) mm (untuk panel dengan ketebalan > 6 mm), ditempatkan sejajar penyangga dan berjarak sama terhadap kedua penyangga.

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Dokumen acuan berikut penting untuk pelaksanaan standar ini. Untuk acuan tertanggal, hanya sebagian edisi kutipan yang akan berlaku. Untuk acuan tidak bertanggal, edisi terakhir dokumen acuan yang berlaku (termasuk amandemennya):

SNI ISO 16978:2010

Wood-based panels — Determination of modulus of elasticity in bending and of bending strength

1

Scope

This International Standard specifies a method for determining the apparent modulus of elasticity and bending strength of wood-based panels in flatwise bending.

2

Normative references

ISO 9424, Wood-based panels — Determination of dimensions of test pieces ISO 16999, Wood-based panels — Sampling and cutting of test pieces

3

Principle

The modulus of elasticity in bending and bending strength are determined by applying a load to the centre of a test piece supported at two points. The modulus of elasticity is calculated by using the slope of the linear region of the load-deflection curve; the value calculated is the apparent modulus, not the true modulus, because the test method includes shear as well as bending. The bending strength of each test piece is calculated by determining the ratio of the bending moment M, at the maximum load Fmax, to the moment of its full cross-section. 4

Apparatus

4.1

Measuring instruments, as specified in ISO 9424.

4.2

Testing apparatus, having the following essential components (see Figure 1).

4.2.1 Two parallel, cylindrical, roller-bearing supports, of length exceeding the width of the test piece and of (10 ± 0,5) mm diameter for panels of nominal thickness <, 6 mm and of diameter (15 ± 0,5) mm for panels of nominal thickness > 6 mm. The distance between the supports shall be adjustable. 4.2.2 Cylindrical loading head, of the same length and (10 ± 0,5) mm in diameter for panels of nominal thickness ≤ 6 mm, and (30 ± 0,5) mm in diameter for panels of nominal thickness > 6 mm, placed parallel to the supports and equidistant from them.

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The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

SNI ISO 16978:2010

Ukuran dalam milimeter

CATATAN

I1 ≥ 20 t l2 = l1+50 Ø d1 = Ø d2 = 10 ± 0,5 untuk t ≤ 6 Ø d1 = 30 ± 0,5 ; Ø d2 = 15 ± 0,5 untuk t > 6

pengaturan alternatif boleh dilakukan asal hasilnya dapat dipertanggungjawabkan

Gambar 1 — Penyusunan alat uji lentur 4.2.3 Deflektometer, mampu mengukur defleksi contoh uji di tengah-tengah bentangan dengan ketelitian hingga 0,1 mm. 4.2.4 Sistem pengukuran, mampu mengukur beban yang diberikan pada contoh uji dengan ketelitian hingga 1% dari nilai yang diukur.

5 5.1

Contoh uji Pengambilan panel contoh dan pembuatan contoh uji

Pengambilan panel contoh dan pembuatan contoh uji sesuai ISO 16999. Diperlukan rangkaian contoh uji baik pada arah longitudinal dan arah melintang. 5.2

Dimensi contoh uji

Contoh uji berbentuk persegi panjang, dengan dimensi sbb: Kecuali ditentukan lain, lebar b harus (50±1) mm

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Keterangan : 1 potongan uji F beban t tebal potongan uji

SNI ISO 16978:2010

Dimensions in millimetres

NOTE

I1 ≥ 20 t l2 = l1+50 Ø d1 = Ø d2 = 10 ± 0,5 for t ≤ 6 Ø d1 = 30 ± 0,5 ; Ø d2 = 15 ± 0,5 for t > 6

alternative arrangement may be used if a valid correlation to the specified arrangement can be proven

Figure 1 — Arrangement of the bending apparatus 4.2.3 Suitable instrument, capable of measuring the deflection of the test piece in the middle of the span with an accuracy of 0,1 mm. 4.2.4 Measurement system, capable of measuring the load applied to the test piece with an accuracy of 1 % of the measured value.

5 5.1

Test pieces Sampling and cutting

Sampling and cutting of the test pieces shall be carried out according to ISO 16999. Series of both transverse and longitudinal test pieces are required. 5.2

Dimensions of test pieces

The test pieces shall be rectangular, and of the following dimensions: Unless otherwise specified the width b shall be (50 ± 1) mm.

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Key 1 test piece F load t thickness of the test piece

SNI ISO 16978:2010

Dalam hal panel ekstrusi (extruded panels), panel seluler (celluler panels), atau panel berstruktur serupa yang mempunyai rongga sejajar terhadap panjang contoh uji, lebar contoh uji minimal dua kali lebar unsur inti (dalam hal ini dua kali diameter rongga ditambah dua kali tebal sekat) dan contoh uji harus berpenampang lintang simetris seperti terlihat pada Gambar 2. Pada contoh uji dengan kecenderungan saluran/alur tegak lurus panjang, kepala beban diletakkan tepat diatas jaringan (web). Ukuran dalam milimeter

Panjang l2 sekurang-kurangnya 20 kali tebal ditambah 50 mm, dengan panjang maksimum 1050 mm dan minimum 150 mm. Jika tidak terjadi patah, jarak sangga harus dikurangi untuk uji keteguhan lentur. Laporan hasil uji harus mencantumkan data jarak sangga pada saat gagal uji. Jika prosedur ini diadopsi, harus digunakan serangkaian contoh uji yang baru. Contoh uji kayu lapis harus bebas dari cacat yang dapat mengurangi kekuatan. 5.3

Pengkondisian

Contoh uji harus dikondisikan sampai mencapai berat konstan pada ruangan dengan kelembaban relatif (65 ± 5) % dan suhu (20±2) °C. Berat konstan dicapai apabila dalam dua kali penimbangan dalam rentang waktu 24 jam, tidak berbeda lebih dari 0,1%.

6 6.1

Prosedur Ukur lebar dan tebal tiap contoh uji sesuai ISO 9424, pada tempat-tempat berikut: - tebal pada perpotongan diagonal - lebar pada pertengahan panjang

6.2 Atur jarak sangga minimal 20 kali tebal panel dengan kelipatan 1 mm, tapi tidak boleh kurang dari 100 mm dan tidak lebih dari 1 000 mm. Ukur jarak sangga, dengan pembulatan 0,5 mm terdekat. 6.3 Letakkan contoh uji dengan posisi rebah pada penyangga, sedemikian sehingga titik pembebanan terletak pada tengah-tengah contoh uji (lihat Gambar 1).

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Gambar 2 — Penampang melintang papan tubular

SNI ISO 16978:2010

In the case of extruded panels, cellular panels, or panels of similar structure with cavities parallel to the length of the test piece, the width of the test piece shall be at least twice the width of an individual core element (e.g. two tube diameters plus two web thicknesses) and the test pieces shall have a symmetrical cross-sectional area as shown in Figure 2. In test pieces with cavities perpendicular to the length, the loading head shall be located directly above a web. Dimensions in millimetres

The length l2 shall be at least 20 times the nominal thickness plus 50 mm, with a maximum length of 1 050 mm and a minimum length of 150 mm. If the deflection of the test piece is such that rupture (failure) does not occur, the distance between supports shall be reduced for testing the bending strength. The test report shall include the distance between supports at which failing tests were conducted. If this procedure needs to be adopted, a new set of test pieces shall be used. Plywood test pieces shall be free of visible strength-reducing characteristics. 5.3

Conditioning

The test pieces shall be conditioned to constant mass in as an atmosphere with a relative humidity of (65 ± 5) % and a temperature of (20 ± 2) °C. Constant mass is considered having been reached when the results of two successive weighing operations, carried out at an interval of 24 h, do not differ by more than 0,1 % of the mass of the test piece.

6

Procedure

6.1 Measure the width and thickness of each test piece according to ISO 9424 at the following points: — the thickness at the intersection of the diagonals; — the width at the mid-length. 6.2 Adjust the distance between the centres of the supports, to within 1 mm of at least 20 times the nominal thickness of the panel, but not less than 100 mm and not more than 1 000 mm. Measure the distance between the centres of the supports to the nearest 0,5 mm. 6.3 Place the test piece flat on the supports, with its longitudinal axis at right angles to those of the supports with the centre-point under the load (see Figure 1).

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Figure 2 — Cross-section of tubular boards

SNI ISO 16978:2010

6.4 Beban diberikan dengan laju pembebanan tetap. Laju pembebanan dinaikkan sampai pembebanan maksimum dicapai dalam (60±30) detik. Ukur defleksi pada tengah-tengah contoh uji (di bawah kepala beban), hingga ketelitian 0,1 mm, kemudian plotkan nilai ini terhadap beban yang diberikan hingga ketelitian 1% dari nilai terukur. Jika defleksi ditentukan melalui pembacaan yang kontinyu (kenaikan terus menerus), harus digunakan setidaknya 6 kali pembacaan. Catat beban maksimum hingga ketelitian 1%

6.5

7

Pernyataan hasil

7.1

Modulus elastisitas

7.1.1 Modulus elastisitas Eb, dalam Megapascal (MPa), dari setiap contoh uji, dihitung dengan rumus:

l1 ( F2 − F1 ) 4bt 3 (a2 − a1 ) 3

Eb

=

Dimana l1 b t F2-F1 a2 – a1

jarak sangga, dalam milimeter(mm) lebar contoh uji, dalam milimeter (mm) tebal contoh uji, dalam milimeter (mm) kenaikan beban, dalam Newton (N), pada garis lurus kurva beban-defleksi (Gambar 3) (F1 kira-kira 10% dan F2 kira-kira 40% dari beban maksimum) kenaikan defleksi di tengah-tengan contoh uji (akibat dari kenaikan beban F2-F1)

Modulus elastisitas tiap contoh uji dinyatakan dengan tiga angka desimal 7.1.2 Modulus elastisitas tiap kelompok contoh uji yang diambil dari panel yang sama (lihat 6.6) merupakan rataan aritmatik modulus elastisitas, dinyatakan dalam tiga angka desimal.

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6.6 Pengujian dilakukan pada dua kelompok contoh uji menurut dua arah panel (yaitu arah memanjang dan arah melintang). Dalam setiap kelompok, setengah dari jumlah contoh uji permukaaan depannya (face) menghadap ke atas, sisanya permukaan belakangnya (back) menghadap ke atas.

SNI ISO 16978:2010

6.4 The load shall be applied at a constant rate of cross-head movement throughout the test. The rate of loading shall be adjusted so that the maximum load is reached within (60 ± 30) s. Measure the deflection in the middle of the test piece (below the loading head), to an accuracy of 0,1 mm, and plot this value against the corresponding loads measured to an accuracy of 1 % of the measured value. If deflection is determined by incremental readings, at least 6 pairs of reading shall be used. 6.5

Record the maximum load to an accuracy of 1 % of the measured value.

7 7.1

Expression of results Modulus of elasticity

7.1.1 The modulus of elasticity, Eb, in megapascals (MPa), of each test piece, is calculated from the equation:

l1 ( F2 − F1 ) 4bt 3 (a2 − a1 ) 3

Eb

=

Where l1 is the distance between the centres of the supports, in millimetres (mm); b is the width of the test piece, in millimetres (mm); t is the thickness of the test piece, in millimetres (mm); F2 − F1 is the increment of load, in newtons (N), on the straight-line portion of the loaddeflection curve, (see Figure 3) (F1 shall be approximately 10% and F2 shall be approximately 40% of the maximum load); a2 − a1 is the increment of deflection at the mid-length of the test piece (corresponding to F2 − F1). The modulus of elasticity for each test piece shall be expressed to three significant figures. 7.1.2 The modulus of elasticity for each group of test pieces taken from the same panel (see 6.6) is the arithmetic mean of the moduli of elasticity of the appropriate test pieces, expressed to three significant figures.

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6.6 Carry out tests on two groups of test pieces according to the two directions of the panel, i.e. in the longitudinal and transverse directions. Within each group, test half of the test pieces with the “top face” upwards, and half with the “bottom face” upwards.

SNI ISO 16978:2010

Beban F

Gambar 3 — Kurva beban-defleksi dalam kisaran deformasi elastis

7.2

Keteguhan lentur

7.2.1 Keteguhan lentur Rb, dalam Megapascal (MPa), masing-masing contoh uji dihitung dengan rumus: Rb

3Fmaxl1 2bt 2

=

Dimana Fmax l1, b dan t

beban maksimum, dalam Newton (N) lihat 7.1.1

Nyatakan keteguhan lentur tiap contoh uji hingga tiga desimal 7.2.2 Keteguhan lentur tiap kelompok contoh uji diambil dari panel yang sama (lihat 6.6) merupakan rataan aritmatik modulus elastisitas, dinyatakan dalam tiga desimal.

8

Laporan hasil

Laporan hasil pengujian memuat informasi: a. b. c. d. e. f. g. h. i. j. k.

nama dan alamat laboratorium laporan pengambilan contoh sesuai ISO 16999 tanggal laporan pengujian acuan pada standar nasional ini jenis dan ketebalan panel spesifikasi produk perlakuan permukaan, bila ada panjang contoh uji dan jarak sangga alat yang digunakan hasil pengujian, dinyatakan sesuai pasal 7 semua penyimpangan dari standar nasional ini

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defleksi

SNI ISO 16978:2010

7.2

Bending strength

7.2.1 The bending strength Rb, in megapascals (MPa), of each test piece, is calculated from the equation: Rb

=

3Fmaxl1 2bt 2

where Fmax is the maximum load, in newtons (N); l1, b and t are defined in 7.1.1. Express the bending strength of each test piece to three significant figures. 7.2.2 The bending strength for each group of test pieces taken from the same panel (see 6.6) is the arithmetic mean of the bending strengths of the appropriate test pieces, expressed to three significant figures. 8

Test report

The test report shall contain the following information: a. b. c. d. e. f. g. h. i.

name and address of the test laboratory; sampling report according to ISO 16999; date of the test report; reference to this International Standard; type and thickness of the panel; relevant product specification; surface treatment, if relevant; length of the test pieces and distance between supports; specific apparatus used, in case of different possibilities allowed in this International Standard; j. test results expressed as stated in Clause 7; k. all deviations from this International Standard.

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Figure 3 — Load-deflection curve within the range of elastic deformation



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BADAN STANDARDISASI NASIONAL - BSN Gedung Manggala Wanabakti Blok IV Lt. 3,4,7,10 Jl. Jend. Gatot Subroto, Senayan Jakarta 10270 Telp: 021- 574 7043; Faks: 021- 5747045; e-mail : [email protected]

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Panel kayu Penentuan modulus elastisitas lentur dan keteguhan lentur

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