COMPLETE SPECIFICATION
TITLE OF THE INVENTION
5 A STEEL PALLET SYSTEM FOR CARRYING METAL COILS AND METHODS THEREOF FIELD OF THE INVENTION
The present invention relates to entities for logistics in particular economical and durable pallets. 10
BACKGROUND OF THE INVENTION
At present mostly wooden pallets are being used for steel coil transport. Cost of each such wooden palletis highly expensive and weighs around 30kgs. These wooden pallets are scrapped after one 15 use. This is not only a waste of money but also leads to cutting of nearly 15 to 20 years grown uees of 9000 numbers in a year.Alternative metal pallets have been attempted by several Industries in the past by welding components together. But almost all of them were abandoned because of the fatigue failure thai happens during transport reducing their utility life drastically.
20 The main challenge for the metal pallet innovation is that many earlier usage metal pallets have resulted in large loss due to the failure of the material of the components in fatigue. This is due lo the fact llial the metal of the logistic frame/pallets are subjected to millions of cycles of stress during its transportation. This cyclic loading cause cracks and the metal frames fails during transportation causing very heavy losses. Fig. 16 shows how during logistics the metal frames fail in fatigue and cause cracks, causing
25 heavy loss to the merchandise.
Thus, based on the acquired experience and knowledge over the years aninnovative durable steel pallet
design with adismountablesystem rendering strength, utility, fatigue, and failure-free perfonnanceis
developed herewith.
30
Further in order to evolve the new and innovative steel pallets that are fatigue resistant an experimental
evaluationof pallets carrying the coated steel coils over thousands of kilometers in lorries is needed.
SUMMARY OF THE INVENTION
35
The present invention relates to a metal pallet system, with grillages of beams comprising:

a. at least two numbers of primary section with tubes made up of two 100 x 100 x 4.0 sized
square section;
b. at least four numbers of support section with tubes made up of the four numbers of 60 x
60 x 4.0 sized secondary beams.
5
Another aspect of the invention relates to a dismountable pallet system, comprising a plurality of
members made of square hollow sections (SHS) to carry loads weighing approximately but nol limilcd to
5.5 tons.
10 An aspect of the invention relates to a method for design evaluation of steel pallets, wherein the method comprises,
c. Finite Element Analysis of steel pallet to study the stress pattern;
d. Service Load and Static Load Test:
e. Fatigue Test which is the most important component of the investigations.
15
Wherein, the square tubes of primary members and support members are configured as hollow
sections (Square Hollow Sections (SHS)).
Wherein, the grillage of beams made with square hollow sections (SHS) are arranged to make up 20 the metal pallet.
The inventive steel pallets are highly economical. The economy and the fatigue resistance comes
from the orientation of the bolted joints and the carefully arranged bolt hole systems thai are-quite
efficient. The pallet has been designed in a way to have the flexibility, good seating on the transporting
25 vehicle floor while being transported and also to relive harmful fatigue stresses that happen during
transport.
BRIEF DESCRIPTION OF THE DRAWINGS
30 Figure. 1 Shows general arrangement of the pallet.
Figure. 2 Shows the true stress-strain curve of mild steel. Figure. 3 Shows loading and boundary conditions corresponding to lifting case. Figure. 4 Shows mesh pattern of the pallet. 35 Figure. 5 Shows the Load vs Arc length curve for the FE model.

Figure. 6 Shows contour plot of Von mises stress at 8.8 ton load shifting condition.
Figure. 7 Shows Finite Element analysis of FE models prepared for different loading conditions in which the pallets are subjected.
Figure. 8 Shows connection details of the pallets.
5 Figure. 9 Shows points of high stress and deflection obtained from computer analysis.
Figure. 10 Shows strain gauges pasted on high stress regions.
Figure. 11 Shows the pallet under testing with steel coil being lifted.
Figure. 12 Shows maximum strains in the pallet while loading in bending machine(Service load).
Figure. 13 Shows maximum displacement response at ultimate load.
10- Figure. 14 Shows Load Vs Strain diagram at Ultimate Load.
Figure. 15 Shows a typical plot of the cyclic/ fatigue stress being applied in the specimen.
Figure. 16 shows metal frame failure in fatigue and cause cracks, causing heavy loss to the merchandise during logistics.
Referring to the drawings, the embodiments of the present invention are further described. The figures are 15 not necessarily drawn to scale, and in some instances the drawings have been exaggerated or simplified for illustrative purposes only. One of ordinary skill in the art may appreciate the many possible applications and variations of the present invention based on the following examples of possible embodiments of the present invention.
20 DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a metal pallet system, with grillages of beams comprising:
a. at least two numbers of primary section with tubes made up of two 100 x 100 x 4.0 sized
square section;
25 b. at least four numbers of support section with tubes made up of the four numbers of 60 x 60 x
4.0 sized secondary beams.

Another aspect of the invention relates to a dismouniable pallet system, comprising a plurality of members made of square hollow sections (SHS) to carry loads weighing approximately but not limited to 5.5 tons.
5 An aspect of the invention relates to a method for designevaluation of steel pallets, wherein the meihod comprises,
a. Finite Element Analysis of steel pallet to study the stress pattern;
b. Service Load and Static Load Test:
c. Fatigue Test which is the most important component of the investigations
10
Wherein, the square tubes of primary members and support members are configured as hollow
sections (Square Hollow Sections (SHS)).
Wherein, the grillage of beams made with square hollow sections (SHS) are arranged lo make up 15 the metal pallet.
One embodiment of the invention relates toa durable steel pallet design with a dismouniable system rendering strength, utility, fatigue failure-free performance.
20 One embodiment of the invention relates to the innovative shape and sizing of the metal brackets
which joins the tubular component of the pallet.
One embodiment of the invention relates to the pallet design with dismoitntable system,developed in a manner which can be mounted during the onward trip carrying the steel coil load and dismounied 25 • during the return trip.
One embodiment of the invention relates toa practice of mounting and demounting of steel pallets
during transportation, wherein the said practiceenables these steel pallets to be re-used for many years
eliminating scrap.
30
One embodiment of the invention relates to the evaluation of the design of sieel palleis for
carrying metal coils weighing around 5.5 tons.
One embodiment of the invention relates to brackets fitting in new steel pallet where, the brackets 35 can be placed in any location of the pallet i.e. the brackets are interchangeable.

One embodiment of the invention relates to exact positioning of the connecting brackets of the steel system, wherein the said positioning reduces the fatigue stresses by bringing in flexibility into ihe steel pallet system and renders enough strength.
5 The frame required to transport rolled coated steel coils or any such similar products are called
pallets which are usually made of wooden planks. This frame is innovated using steel and named as A1YYA DAND
Traditionally, rolled color coated coils are wrapped with I-IDPE sheets and their both end 10 perimeters were covered with steel edge covering straps to prevent the edges from damage during transit and handling and the rolled steel coil is tied to pallets by means of steel straps al 4 sides of the round coil.
Conversion of the wooden pallet to AIYYA DAND is made to overcome the difficulties in getting the wood, high cost, assembling and handling of wooden pallets as well as zero return value on 15 scraps more over this eliminates unsafe condition during handling and transportation.Square / Rectangular Steel Tubes (RHS & SHS) are selected and its sizes are based on the requirement to design pallets.
The main challenge for the metal pallet innovation is thai many earlier usage metal pallets have
resulted in large loss due to the failure of the material of the components in fatigue. This is due to ihe fact
20 that the metal of the logistic frame/pallets are subjected to millions of cycles of stress during its
transportation. This cyclic loading cause cracks and the metal frames fails during transportation causing
very heavy losses.
The invention uses bolted system to bring flexibility in the steel pallet design. Welding was
25 avoided in order to rake no chance in fatigue failures. The biggest challenge was ihe pallet musi be strong
enough to carry the steel coil loads and also flexible enough to seat properly on the floor of the transport
vehicle. Hence a dismountable system was planned. The bracket and bolts were designed. The
innovative part of the proposed ihventionarises from the shape and sizing of the melal brackets which
joins the tubular component of the pallet. The brackets were oriented so that leasi fatigue stresses are
30 caused during the transportation. The extra enabling slots were provided so that the straps can be easily
wound over the steel coil and the pallet. The most innovative pail of the pallet design in thai, it is
mounted while it is carrying the steel coil toad on the onward trip and dismounted during the return trip.
This demounting of these pallets creates space for nesting during return transportation of the pallets. This
mounting and demounting causes these steel pallets to be re-used for many years, without having io scrap
35 them. One important innovation in this new steel pallet is that ihe brackets can be filled in any locaiion
of the pallet in other words they are interchangeable. Hence during the return trip of the pallets, these

brackets don't have to be grouped. Only three sets of tubular members are required. This makes mounting and dismounting a very quick process and hence saves a lot of time.
Envisaging the long term usage, handling of pallets: life cycle of pallet, transportation 5 feasibilities, durability, compatibility, workability and cost effectiveness, the design evaluationof AIYYA DAND for carrying metal coils weighing around 5.5 ton is carried out the in the following 3 stages:
2. Finite Element Analysis of steel pallet to study the stress pattern
3. Service Load and Static Load Test
4. Fatigue Test- which is the most important component of the investigations
10
Where, the details of these three investigations are described in the following sections.
STUDY AND ANALYSISSECTFON
15 A grillage of hollow section beams are arranged to make up the steel pallet. Initially rectangular
hollow section (RHS) members were used for analysis and later optimized lo Square Hollow Sections (SHS) with the tested sizes of 100x100x4.0 Primary members which support the four numbers of 60x60x4.0 secondary beams. The typical pallet is shown in Fig. 1. The main innovation is in the orientation of the brackets and the bolting arrangements to connect these section members. The exact
20 positioning of the connecting brackets are the innovations which reduces the fatigue stresses by bringing in flexibility into the steel pallet system and also strong enough to cany the 5.5 tonnes coil weight.
The methodology adopted herein is to first check the design of the pallet system based on first principles and check the design adequacy and to prepare a finite element model in ABAQUS (a general purpose 25 finite element software), to carry out the advanced analysis and design of the pallet system to evaluate ihe stress distribution. Finally the entire design is checked on the aspect of durability, wear and tear and possible overloads. The details of the study have been briefly presented herewith.
. THE DESIGN CHECKING OF AIYYA DAND
30
As a first exercise the design adequacy of the pallet was done by applying the loads on the
transfer points and the bearing strength of the vertical plate elements of the RHS/SHS section was
checked to be adequate. When the coil weight is being lifted the maximum bending effect happens in ihe
two transverse beams. The bending stresses at the beams flanges are checked to be adequate. The
35 connection points are also checked so that the load transfer can happen between two orthogonal grids of

beams. This check also was carried out lo be safe. After this the entire pallet is modeled in ABAQUS for the stress evaluation of the components of the pallets, which is explained below.
FINITE ELEMENT MODELING 5 Geometry
The geometry of the finite element (FE) model is as per the structural drawings provided by ihe experts. The tubes have been idealized as shell elements. Contact between tubes has been assumed as rigid in the model.
10 Material Property
Material property corresponding to mild steel has been assumed with Young's Modulus of 200 MPa and Poisson's ratio of 0.3. Stress-strain curve adopted is shown in Fig.2.
15 Loading and Boundary Conditions
Boundary conditions (BCs) corresponding to lifting case have been discussed in this section. The meial
coil is assumed lo rest ideally on 4 places and supports are given at 4 ends of the beams as shown in
Fig.3. Uniform pressure has been applied (pink arrows in Fig.3) to represent total load of 1.5 x 5.5 tons of
20 coil weight.
i Meshing and Element Assignment
Uniform mesh of 10 mm element size has been used. Aspect ratio of I has been maintained throughout 25 the finite element model (fig.4). Shell elements have been used to model the tubes as the width to thickness ratio is significantly large.
RESULTS AND DISCUSSIONS
30 A non-linear static analysis was carried out to determine the ultimate load carrying capaciiy of the
pallet system. Rik's solution solver was used to run the analysis. The pallet system withstood a maximum load of 8.8 tons which is evident from Fig.5.
As mentioned earlier, the pallets will be subjected to dynamic loading while transporting metal coils in trucks. So welding the steel tubes together to form the pallets is not'a good option as the welds make the
35 . system rigid and would concentrate stresses along certain portions of the weld line. Due to the nature ol the loading, the welds may give away at highly stressed regions and trigger a complete failure after some

loading cycles. Bolted connections offer relative deformation between the beams because of the tolerance
provided between the bolt and the hole. And hence bolting provides a belter fatigue performance
compared to welding. A 'quarter turn' pretension is required to arrest the excessive play of boll in the
hole. Openings in the tubes must be closed to protect it from corrosion and accumulation of dirt.
5
The second alternate detail (Fig.8) allows tubes to be connected using through and through bolts. This
would save time and effort required to cut and weld bolt access holes.
The methodology adopted by herein is to first assess the strains in the developed pallet system during 10 actual lifting of 5.5 tons steel coils. This is the assessment of the pallet during service load performance. After that the pallets were loaded on bending machine to assess the ultimate static strength of these pallets. The details of the satisfactory experimental performance of the proposed new pallet system arc described in the following sections.
15 EXPERIMENTAL EMBODIMENT
PERFORMANCE OF THE PALLET DURING SERVICE LOAD TESTING
From Fig.9 the points of high stresses during lifting and also the points at which the high deflection will occur are noted. Strain gauges were pasted on the high stress regions in the pallet. Fig. 10 shows the
20 strain gauges pasted and associated wiring for instrumentation. These wires were connected to a data logging system in which the strains are measured as micro strains. These recorded strains are used as indicators to decide how much of the materia! strength is utilized while the coil is being lifted. The coil 10 be lifted (around 5.5 Tonnes) is placed on the pallet. The strain gauges were initialized and checked for their integrity. Then the coil was lifted along with the pallet. During the actual lifting (which is called as
25 the service load lifling) there was no sign of any distress in the steel pallet. The maximum strains measured in the pallet during lifting of actual coil was around 200 micro strain only as shown in Fig.l I, whereas the yield stress of the IS:2062 steel is 1200 micro strains. This shows that the behavior of the pallet is linear and hence the service load behavior of the pallet is excellent. The deflection measurements could not be carried out in this service lifting test. Hence the pallet was tested for its service and uln'maic
30 load performance in a 40 T capacity bending machine. This test is explained in the next section.
PERFORMANCE OF THE PALLET DURING ULTIMATE LOAD TESTING UNDER A BENDING MACHINE

After the service load lifting test the pallet was loaded in 40T bending machine, again the strain gauges were pasted on the high stress regions in the pallet. In addition to that LVDTs were placed under, ihe pallet to measure the deflections while static load being applied- The strain and LVDT readings were recorded in the data logging system. From Fig.12 it can be seen that up to a loading of around 6 Tonnes 5 the strains in the pallet is well below 250 micro strains while the yield strain of the material is around 1200 micro strains. After this test, the loading was increased to the ultimate load. The load was increased to more than I I Tonnes. This load is near to a factor safety of 2 against failure. Even at this load, ihe displacements under the pallet were around 4 mm only as seen from Fig. 13. The strains shown in Fig. 14 also proved that even at the ultimate load of two times the service load ihe pallet behaved linearly and 10 hence the behavior of the steel pallet is satisfactory even at the ultimate load level. After the tests were over the pallet was inspected for any damage to the members or even the connections. No appreciable and significant damage was noted even after the pallet was subjected to service and ultimate loads. The two tests proved beyond doubt that the steel pallet is adequate and stable in carrying loads.
15 SUMMARY AND CLOSURE FOR STATIC TESTS STEEL PALLETS
The above write up deals with the experimental evaluation of steel pallet system to carry coated
metal coils weighing 5.5 tons and also to ascertain the ultimate load capacity. The pallet system consisting
of four numbers of 60 x 60 x 4.0 square tubes resting on two 100 x 100 x 4.0 square tubes were found to
20 be adequate to support the 5.5 ton metal coil. This has been proved by experimental lifting of ihe 5.5 ton
colls and also subjecting the pallet to an ultimate load of close I I tons.
It has been proved experimentally that the steel pallet system is found to be adequate as it satisfies for both strength and stiffness requirements for both service and ultimate load conditions. The 25 steel pallet system also behaved linearly up to a factor of safety of nearly 2.
FATIGUE TEST - METHODOLOGY
The main challenge for the metal pallet innovation is that many earlier usage metal pallets have resulted 30 in large loss due to the failure of the material in fatigue. This is due to the fact that the metal of the logistic frame is subjected to millions of cycles of stress during its transportation. This cyclic loading cause cracks and the metal frames fails during transportation causing very heavy losses.
The methodology adopted herein is to first assess the most important test of the steel pallet, the fatigue
35 performance of steel pallets. A fatigue testing machine capable of applying cyclic load, which will
simulate the cyclic stresses that will be produced when the pallets are loaded in the Lorriesis used. Unless

the fatigue damage is handled properly metal pallets cannot survive fatigue loading during transport. However the present scheme implements a novel method to relieve the fatigue stresses and designed to be fatigue proof.
5 PERFORMANCE OF THE PALLET DURING FATIGUE LOAD TESTING
The pallet was loaded by circular plate which will resemble the actual loading that will come up during transportation. Using the loading jack cyclic load was applied on the pallet which will replicate Ihe fatigue/cyclic loading they will come up during the life of the steel pallet. The loading was applied 10 around 4.5 Hz frequency. Fig. 15 shows a typical cyclic stress that is applied on the specimen.
SUMMARY AND CLOSURE FOR FATIGUE STUDY
The steel pallet withstood 2 million cycles of stress and PASSED the.fatigue test and it is found to be tit 15 for use in real coil transport. The fatigue stresses prove that the innovative steel pallet has withstood not only static stresses but also fatigue stresses more than 2 million cycles of stress.
Il may be appreciated by those skilled in the art that the drawings, examples and detailed description herein are to be regarded in an illustrative rather than a restrictive manner. 20
25
30
35

We Claim:
I. A metal pallet system, wherein the said pallet system is made of steel comprising grillage ol beams containing:
a. at least two numbers of primary members;
b. at least four numbers of secondary(support) members;
c. a plurality of connecting brackets;
d. a plurality of bolts and bolting arrangements.
2. A dismountable pallet system, comprising a plurality of members made of Square Hollow Sections (SHS) to carry loads weighing approximately but not limited to 5.5 tons.
3. According to any of the claim, wherein the square tubes of primary members and secondary membersare configured as hollowsecfions (Square Hollow Sections (SHS)).
4. According to any of the claim, wherein the grillagewith square hollow sectionsof beams are made up of two 100 x 100 x 4.0 sized primary square section and the four numbers of 60 x 60 x 4.0 sized secondary beams are arranged to make up the metal pallet.
5. According to any of the claim, wherein the connecting brackets are oriented, sized unci shaped in a manner to reduce fatigue stresses caused during the transportation.
6. According to any of the claim, wherein the connecting brackets are positioned exactly and can be interchangeably fitted toreduce the fatigue stresses by drawing in flexibility.
7. According to any of the claim, wherein the bolting arrangements are applied to connect the SHS members and bolted connections offer relative deformation between the beams providing a tolerance between the bolt and the hole.
8. According to any of the claim, wherein thepallet is configured as a dismountable system.
9. According to any of the claim, wherein the said dismountable sysleni is designedio be mounted while carrying the load during onward trip and dismounted during return trip.
10. Method for design evaluation of a new steel pallet system for carrying loads, wherein the said method comprise, i) Finite element analysis of the steel pallet to study the stress pattern: ii) Service load and static load test; and iii) Fatigue test.