9/20/2018

Wood Pallets and Unit Load Design: An International Expansion

Welcome Message

Ingredients don’t bake themselves into a cake. Only the application of wisdom and ingenuity can deliver something of greater value than the components. Kristen DeLack, PE Structural Engineer

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There are billions of pallets in service, supporting international trade.

Outline

• Introduction • Languages • Wood and Nails • International Species • Connection Strength • Storage & Handling • Transportation • Unit Load Design • System Level View • Optimization • Question & Answers

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Questions for You

1. International Species a) What international species classes are you interested in? b) Can you help donate material for or sponsor testing? c) Can you provide regulatory body or industry sponsored mechanical property data?

2. What design challenges do you have?

International Expansion

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Multiple Languages may be needed

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Wood & Nails

International Species

Storage & Handling Connection Design

Transportation

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International Species

A wide variety of hardwood and softwood species is used in pallet construction.

Mechanical properties vary between species and growing region.

Two ways to test properties: • Full size pallet components • Small clear samples

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International Central and South American European Species Classes Species Classes Species Classes Prioria Copaifera Imported Hardwoods Radiata Pine Mengkulang Oceanian Species Classes (Chile) Kapur Radiata Pine Gmelina Arborea Keruing (Australia) (Costa Rica) Dense European Hardwoods Maritime Pine, Pinus Pinaster Pinus Caribaea Ash: European (Australia) (Venezuela) Beech: European Radiata Pine Pinus Elliottii Oak: European (New Zealand) (Brazil) Plane: European Pinus Taeda Dense European Softwoods (Brazil) Douglas-fir Eucalyptus Grandis Larch: European, Japanese SE Asian Species Classes (Uruguay) Pine: Maritime, Scots, Jack Anisoptera Ponderosa Pine Medium Dense Woods (Malaysia) (Mexico) Poplar: Grey, Black Italian Anisoptera Pinus Patula Elm: Dutch (Philippines) (Mexico) Redwood Shorea Ocote Pine Fir: Silver (Philippines) (Mexico) Larch: Hybrid Dryobalanops Pine: Lodgepole, Corsican Fir: Silver African Species Classes Whitewood Pinus Patula Elm: English East Asian Species Classes (Madagascar) Spruce: Sitka (Canada) Sugi, Japanese Cedar, Crtomeria Melina Wood, Gmelina Arborea Whitewood japonica (Japan) (Nigeria) Japanese Larch, Lariz Kaempferi Pinus Patula Common European Softwoods (Lmab/) Carriere (Japan) (S. Africa, Mpumalanga & KZN) Pine: Radiata Maritime Pine, Pinus Pinaster Spruce: Black, Norway (S. Africa, Mpumalanga & KZN) Willow: White National Wooden Pallet Pinus Patula Spruce: White, Sitka (U.K., Eire) page (Tanzania) Hybrid Poplar & Container Association Black Alder, Alnus Glutinosa 010

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Testing Full scale pallet components

UK/Ireland: • Scots pine • British spruce

Australia: • Radiata Pine

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Storage & Handling Connection Strength

Fastener Properties

Stiffness

Strength • Fastener withdrawal • Head Pull Through • Lateral strength

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Fastener Properties

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Nail Bending Strength

MIBANT: Morgan Impact Bend Angle Nail Test

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Joint stiffness Moderately important

Stiff Connection

Lower stress in board Lower deflection

Flexible Connection

Higher stress in board Higher deflection

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Connection Strength – Perimeter base block pallet example

Nails RAL Safe Load Deflection @ 1000 lbs Critical Member 2 1085 lbs 0.53” Butted Board to Block (Lateral) 3 1494 lbs 0.48” Center Top Stringerboard 4 1477 lbs 0.46” Center Top Stringerboard

38% additional capacity by adding six nails National Wooden Pallet page & Container Association 016

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Connection Strength – Fork tine support example

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2 Fork Tine Tip Supporting Lifting Safe Load Critical Member 3rd board 2175 lb TD Interiorbd to Stringer (Withdrawal) 2nd board 3381 lb Interior Top Deckboard 2nd board (poor fastener) 1909 lb TD Interiorbd to Stringer (Withdrawal)

National Wooden Pallet 55%+ additional capacity by providing better support page & Container Association and avoiding very poor nails 017

Forklifting From Side of Stringer Pallets

• Tested over 200 simulated forklift notches

• No degradation due to presence of notch corners was observed

• Compression damage opposite the fork tine occurred before break

• Lifting capacity from the side of stringer pallets can be much higher than from the end

• Included in PDS 5.6

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Lateral Collapse

Loss of stability subjected to transportation accelerations

Qualitative Analysis

Transit Analysis

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Lateral Collapse

• Fully updated lateral collapse model

• Capable of providing an estimate for acceleration limit for pallets only restrained at the bottom deck

Acceleration Acceleration acting Acceleration acting Mode of transport acting forwards backwards sideways Road vehicle 1.0 g 0.5 g 0.5 g Railway Subject to shunting 4.0 g 4.0 g 0.5 g Combined (intermodal) transport 1.0 g 1.0 g 0.5 g Sea Baltic sea 0.3 g 0.3 g (b) 0.5 g North sea 0.3 g 0.3 g (c) 0.7 g Unrestricted 0.4 g 0.4 g (d) 0.8 g

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Lateral Collapse Analysis

General (Default) Output

Transit G-force Analysis

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Unit Load Design

Applied Research

Pallet Design & Analysis Product Differentiation Checklist  Design for requirements  Manufacturability Box Design & Analysis  What Materials? Substitutions?  Design optimization  Efficient use of materials  Lifecycle cost  Analysis vs. testing…  Drawings, datasheet, analysis results

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Stretch Wrap

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Box Crush Testing

• Over 400 boxes of varying sizes and materials have been tested

• Effects of high humidity were investigated

• Testing determines stiffness and failure characteristics of each box used in the analytical model

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Unit Load Research –Block Pallet Testing

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Full Scale testing

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Stringer Pallet Unit Load Testing Racked Across Width

Analytical Model

Laboratory Test National Wooden Pallet page & Container Association 027

Load Sharing During Racking Across Width

A portion of the load is carried by the boxes National Wooden Pallet and a portion is supported by the pallet page & Container Association 028

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Racked Across Length, Medium Boxes, Peri. Base Block Pallet Box Compression Stress

Pallet Designs Tested 40% increase in box stress for B0 – Extremely Flexible RAL with half B1 – 0.375” top deck as thick boards boards, 0.5” elsewhere B2 – 0.5” boards B3 – 0.625” boards B4 – 0.75” boards B5 – 0.5” boards, unidirectional base Higher stress under 2nd pallet due to missing boards

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Critical Box Compression

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Racked Across Length, Medium boxes Pallet Stress

Big reduction in stress page 031

Questions & Answers

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Thank You.

Fredells Travaru AB

Super Global

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