|
Artículo Científico / Scientific Paper |
|
|
|
|
https://doi.org/10.17163/ings.n28.2022.09 |
|
|
|
pISSN: 1390-650X / eISSN: 1390-860X |
|
|
STRUCTURAL AND MODAL ANALYSIS OF ADAPTER PLATES FOR
HYDRAULIC HAMMERS AND SKID STEERS UNDER REAL WORK CONDITION |
||
|
ANÁLISIS ESTRUCTURAL Y MODAL DE LAS PLACAS ADAPTACIÓN PARA MARTILLOS HIDRÁULICOS Y MINICARGADORES EN CONDICIONES REALES DE OPERACIÓN |
||
|
Yuri Villa1,
* |
|
Received: 16-05-2022,
Received after review: 13-06-2022, Accepted: 15-06-2022, Published:
01-07-2022 |
|
Resumen |
Abstract |
|
En Perú la necesidad de proyectos de servicios como la instalación de redes de gas para los residentes ha incrementado la demanda del uso de martillos hidráulicos (HH) con minicargadores debido a la baja inversión en comparación con otros equipos de maquinaria y la versatilidad. La facilidad para intercambiar martillos hidráulicos con cucharones para completar las etapas de demolición y limpieza ofrecen una alta productividad en comparación con una operación manual para los contratistas. Por esa razón, el software de diseño virtual Inventor Professional fue usado para diseñar una placa de adaptación con la resistencia y durabilidad adecuadas lo cual tiene un impacto directo sobre la estructura del martillo hidráulico y el brazo hidráulico del minicargador. Simultáneamente, se desarrolló una animación básica para explicar el efecto del estilo de operación sobre los martillos hidráulicos y las placas de adaptación. Finalmente, para este desarrollo, se consideró la construcción de la placa de adaptación como un fusible en el sistema en caso de que los operadores excedan la capacidad de resistencia de la estructura del martillo hidráulico. |
In Perú the
necessity of facility projects such as gas line installation for residents
has increased the demand for use of Hydraulic Hammers (HH) with Skid Steers
due to the lower amount of investment needed in comparison to other packs of
machinery and the versatility. The ability to interchange hydraulic hammers
and buckets to complete the demolition and cleaning stages offers higher
productivity than manual operations for contractors. For that reason, the
virtual design software Inventor Professional was used to design a suitable
adapter plate with adequate resistance and durability which has a direct
impact on the structure of the hydraulic hammer and the hydraulic arm of the
skid steers. Simultaneously, a basic animation was developed to explain the
effect of the operation style over the hydraulic hammer and the adapter
plate. Finally, for this development, the construction of an adapter plate as
a fuse in the system was considered in case operators exceed the resistance
capacity of the hydraulic hammer structure. |
|
Palabras clave: Diseño, martillo hidraulico, minicargadores, platos adaptadores, Inventor Profesional, Ansys |
Keywords: Design, hydraulic hammer, skid
steer, adapter plate, Inventor Professional, Ansys |
|
1,*Department of
Biological and Agricultural Engineering, North Carolina State University,
United States. Corresponding
author ✉: yvillar@ncsu.edu. 2École Nationale Supérieure Agronomique de Toulouse, Institut National Polytechnique de Toulouse, France. 3Departamento de Gestión empresarial, Universidad Nacional Agraria la Molina, Lima. 4Facultad de Ingeniería y Arquitectura, Universidad de San Martin de Porres, Lima. 5Facultad de Ciencias e Ingeniería, Pontificia Universidad Católica del Perú, Lima.
Suggested
citation: Villa, Y.; Vook, T.; Villa, J. L.;
Carbajal, P.; Barrera, L. y Florez, M. “Structural
and Modal Analysis Of Adapter Plates For Hydraulic Hammers And Skid Steers
Under Real Work Condition,” Ingenius, Revista de Ciencia y Tecnología, N.◦ 28, pp. 1-10, 2022, doi: https://doi.org/10.17163/ings.n28.2022.09 |
|
1.
Introduction In South
America, it is common to build roads without service nets installed because
the executed facility projects are limited by investment capital. The
necessity to improve the quality of life and to expand services for residents
opened a huge market for demolition products such as hydraulic hammers [1]. Projects such as gas
pipe installations require building trenches, beginning with the cutting of
hard surface concrete pavement or asphalt to create, on average, 20 cm wide
openings. For demolition, hydraulic hammers mounted on a compact skid steer
are used, which can also be utilized to clean the removed waste material and
for restoration [2]. In Peru, for natural
gas massification construction projects, a Case
Skid Steer model SR220 and Hydraulic Hammer SB202 were used. The hammer has
special features such as a solid body structure, a grease refilling valve
located on the top of the body, and the narrowest box section width of 17 cm,
which reduces the energy invested over kilometers of gas pipe installation
[3]. At the same time,
the demand for new operators and contractors to install gas pipes boosted the
demand for systems of skid steer- adapter plate- hydraulic hammer. Due to
dealer´s market strategies, the focus on the importance of the adapter plate
and their potential impact on the performance and useful time of hydraulic
hammers were lost. The demand for training, new strategies and different
solving proposals increased when the rate of claims rose from 5% to 35%,
particularly for irreparable damages in hydraulic hammers [4]. Independent research
using advanced virtual analysis was made by the major local adapter plate
manufacturer “Soluciones Barrera EIRL”, which had a
participation of 60% of products in the closed market of Atlas Copco SB202
and Case SR202. This company is one of the most innovative ones in the
Peruvian market. After evaluation of
the nature of the failure and the recurrence, a relation was detected between
poor operation skills, the extreme resistance and hardness of the adapter
plate, and the presence of other manufacturers of adapter plates without
adhering to engineering standards. Similarly, the focus was not on the
evaluation and the control of damaging effects [5]. As a result, an
objective was set to build the adapter plate as a fuse in the system. Static
and dynamic virtual simulation were used to design a new adapter plate with
Inventor Professional. Afterward, Ansys analysis
confirmed the behavior. Complimentary with the registration of performance and
claim records, a group of adapter plates was made to improve the building
process, product quality, and finally cost reduction. |
2.
Materials and
Methods
2.1.
General
overview
In 2004 the Camisea
Gas project, which cost 3.9 billion dollars (USD), began a gas massification process in Peru. Due to the intensiveness
of this activity, a method was set to install pipelines in the soil in a
depth of 30 cm, this depth created the technical recommendation to build
trenches with a depth of 70 cm. Some work was in streets paved with concrete
or asphalt and for that reason, it was necessary to demolish the hard road
surfaces that were previously cut in widths of 20 cm [6, 7] (Fig 1).
Figure 1. Trench building demolition and excavation [8] Historical reference
sales from 2014 for a group of 15 new skid steer, adapter plate, and
hydraulic hammer systems showed a high number of warranty claims resulting
from failures on the solid body of the hydraulic hammers. After a thorough
evaluation using a penetrant liquid, the formation of cracks on hydraulic
hammers was detected. An investigation was
performed to understand the failure origin, which was related to the overload
on the hammer. A possible explanation was extrapolated due to other failures
in moil points, bushings, and pistons. At the same time, 4 skid steers showed
initial microcrack formation in their arms.
Consequently, a hypothesis was established considering the system of skid
steer - adapter plate - hydraulic hammer as a single unit where vibration and
resonance generated during the demolition process traveled through the system
and produced cracks in the least tough part of the system. As a second part
of the method, a new prototype considering the adapter plate as a fuse was
established and is explained in this research [9]. 2.2.
Skid- steers a
multipurpose machine Skid-steers are used in different industries as multipurpose compact carriers for construction, handling materials vehicles, and agriculture equipment [10]. In |
|
combination with hydraulic hammers,
some methods of demolition can be made, using as a recommendation the
specification of hydraulic flow rate, static pressure, and the hammer weight
resistance detailed as a reference [11]. Additionally, the
decision of the size of the bucket was in relation to the density of material
handled, in this case, old concrete or asphalt 5-20 cm thick and compacted
soil was lifted from the surface into trucks as waste material. In this
experience, the model SR220 from Case was mounted with 240 kg heavy-duty
buckets with a capacity of 0.44 m3 reported by customers and
supported by the brochure [12]. 2.3.
Selection of
hydraulic hammer for operation condition Boundary conditions were the minimum
width of the trench, the depth of 70 cm and, as operations were inside the
trench, the hammer lubricator nipple located by its design on the top of the
hammer. A hammer with higher resistance for overload and built with minimum
internal parts were used under endurance conditions. For that reason a Case
Skid Steer model SR220, equivalent to Caterpillar model 236B was selected
with a hydraulic breaker Atlas Copco SB202 with a solid body [13]
(Fig. 2).
Figure 2. Hydraulic Hammer SB202 Atlas Copco [3] 2.4.
Impact on the
skid steer and hydraulic breaker durability Good maintenance and adequate
design of the adapter plate for Hydraulic hammer allows to obtain the maximum
result. Diagnostic tests were made to detect minor failures in order to fix
them, which is an important part of a preventive maintenance program. |
Contractors reported an
operative availability between 61% and 81% after a strategic plan was applied
to improve it [14]. The standard
configuration was the use of SB202 due to its special features its patent
design, resistance for overloads and higher location of the lubrication
valve. The reliability of the hammer was not measured but was reported by
contractors as higher than other products that they used. 2.5.
Real work
conditions Crack formation as a result of the
use of the hydraulic hammer was reported by Li et al. (2019) [15]
using Ansys Workbench which showed the behavior in
the arm structure in an articulate system, when a hydraulic hammer is used.
Fundamental parameters about the potential impact and crack formation were
taken referentially from the registered real operations. The hypothesis was
to test the adapter plate as a fuse to protect the hammer and skid steer
integrity, considering the maximum overload condition when operators use
excessive hydraulic pressure with the arms-hammer over the surface for
demolition, and in a non-aligned 90° angle of operation (between the hammer
and the surface). This can be considered the most extreme operation condition
and, for that reason, a line of research was open to optimize the adapter
plate (Fig. 3).
Figure 3. Skid Steer working with Hydraulic Hammer SB202 [16] 2.6.
Fabrication of
adapter plate Physical
measurements were taken from the hydraulic hammer Atlas Copco SB202 and the
top mounting region of the arm, taking into consideration the tridimensional
measurements to connect both machines and, afterwards a tridimensional
drawing was developed using the software Inventor Professional and Ansys to analyze the static structural and dynamic
behavior under maximum impact frequency of 1800 blows per |
|
minute (BPM). For
the analysis, the adapter plate was made independent from the system of the
skid steer arm and the hydraulic hammer. Boundary conditions such as gravity,
the weight of 16,750 N applied to the adapter plate and hydraulic force in
contact regions with the hammer and the skid steer arm were applied. 2.7.
Criteria for
adapter plate redesign The redesign of the adapter plate
was made considering a soft material in the first stage of analysis, and
following the results of the first six months, those were redesigned using a reinforcement
which increased the lifetime to over one year of standard operation. The
system skid steer-adapter plate-hammer was used for the demolition of road
hard cover (old asphalt, concrete) and to break the compacted soil structure
(Table 1). Table 1. Boundary
operational conditions for the system Skid steer- adapter plate – hydraulic
hammer
3.
Results and
discussion 3.1.
Static
Analysis Loaded static analysis was performed using Autodesk 2020 Inventor Professional, considering the weight of Skid Steer with attachments of 33,752 N (Table 1); as a result of the operation observed a weight of 16,750N was considered (Fig. 2). Due to the two contact regions between the arm and the adapter plate, a force of 8,375 N was applied to each contact area and a force of 16,750 N was applied to the contact surface between the adapter plate and the hydraulic hammer. (Fig. 4). |
Figure 4. Adapter Plate built in
Inventor For the meshing analysis in Autodesk Inventor 2020 (Fig. 5), the average size element used was 0.05, the minimum size element 0.1, the grading factor 1.5 and the maximum turn angle 30 deg. Geometrically the adapter plate was designed considering flat shapes reducing the presence of curvatures. Referential recommendations are detailed in Table 2.
Figure 5. Adapter Plate Meshing Table 2. Boundary
operational conditions for the system Skid steer-adapter plate- hydraulic
hammer
For the static
analysis, the tensile yield stress of carbon steel ASTM A36 (Table 3) used is
250 MPa., with young’s modulus = 199.959 GPa, and
Poisson ratio = 0.3. (Fig. 6). Assuming a maximum Von Mises Stress of 31.33
MPa (Fig. 6) and a deflection limitation of 0.25 mm, a maximum result of
displacement of 0.09856 mm (Fig. 7) was obtained. |
|
Table 3. Carbon Steel ASTM A36
Properties [17]
Figure 6. Von Mises Stress Static
Analysis in Inventor
Figure 7. Displacement Static Analysis
in Inventor
Figure 8. Maximum Tensile Stress
Static Analysis |
Figure 9. Maximum Compressive Stress
Static Analysis
Figure 10. Safety factor Static
Analysis The
maximum tensile stress of 11.58 MPa (Fig.8) is below the Von-Mises condition
(32.38 MPa) (Fig. 7), because the stress was distributed throughout the whole
structure. The maximum compressive stress was 3.32 MPa (Fig. 9), which was
observed in the support structure interfaces between the hammer base plate
and the skid-steer base plate. The maximum compressive stress of ASTM A36
carbon steel used is 152 MPa [18]. The minimum safety factor was 7.92 (Fig.
7) which means that we achieve a high factor of safety with this design [19]
Table 4. Table 4. Comparison Static and
Dynamic Analysis
|
|
3.2.
Modal Analysis
The impact frequency
of using one SB202 was in a range of 850-1800 blows/min (max 30 Hz). The
total maximum deformation was 3.0405 × 10−6 mm in the contact
region between the adapter plate and hammer and in the central region of the
adapter plate areas with 0.098 mm (Fig. 7). A
stress drop for harmonic analysis was performed in Ansys
Modal and Harmonic Response. As a first analysis, it is usual to evaluate
where the stress relaxations and prestress removal
took place in the adapter plate. Static stress was 11.58 MPa (Table 4) in the
initial stage. As dynamic action starts, this situation gets relaxed first.
Dynamic stress analysis was used to compensate for the static compression and
to bring down the static effect to zero in order to reverse the resistance
developed inside the material. The Dynamic stress
excluding prestress was 12.37 MPa (Fig. 11) and the
total dynamic stress was 23.95 MPa (Table 4). Maximum principal stress and
minimum principal stress percentage difference values of the static and
dynamic results are 48.34% and 42.19% which is less than 50% (Fig. 12).
Figure 11. Harmonic Analysis in Ansys
Max Frequency of 30Hz
Figure 12. Maximum Principal Stress in Harmonic Analysis 3.3. Fatigue Analysis Table 5 shows the resulting fatigue
life analysis reported by Ansys, we had 1.00 × 108
cycles up to structural failure (Fig. 13). For that reason, using the
hydraulic hammer and its operational performance of 600 and 1800 BPM and
correlating with the operational hours |
per day, which
results in a range of 308.64 to 925.93 days of operation before failure. Table 5. Fatigue analysis per operation cycles
Figure 13. Fatigue Life Analysis in cycles Similarly, the
safety factor resulting from the fatigue analysis reported a minimum number
of 4.3599 (Fig. 14) which is over 1 and we can consider this a reliable
design.
Figure 14. Fatigue Analysis- Safety factor Due to the maximum stress of 31.33
Mpa (Fig. 6) with a safety factor of 7.92 (Fig.
10), this sustains up to 1.00 × 108 cycles (Fig. 13) before
structural failure. |
|
This performance
supports the goal of this design attaining the maximum durability while also
acting as a fuse protecting the hammer and skid steer structure if an overload
happens. With the stress load reported it is still under the endurance limit,
because despite the 1.00×108 cycles before fatigue, the safety
factor is over 1 which means we have space for future optimization. 3.4.
Building and
welding process The adapter plate was built using
carbon steel ASTMA36, with welding 6011 and 7018 with 5/32” size and for the
final product an electrostatic paint RAL9005 was used, and each final product
was registered with a progressive registration number for the product quality
control and warranty management (Fig. 15). 3.5.
Standard
product for the market As a marketing strategy, the
supplier offered six months as a standard warranty and included a constantly
updated optimization for final users with high reliability using new adapter
plates as a backup in case of quality problems with the presence of cracks in
the structure (Table 2). Table 6. Record of
adapter plates and qualitative performance
After 14 months of use,
a group of 10 adapter plates built simultaneously were physically evaluated
along with their warranty claims. The results confirmed normal wear during
operation and the presence of cracks after the warranty period of 12 months.
(Table 6) At the same time, no cracks were observed in the solid structure of
hammers or skid steer boom structure, and complementary animation and
training videos were developed to explain the effect of inappropriate
operation to customers [16]. Proper training and operation contributed to
reducing damage to hydraulic hammers. Finally, this
product has been a probed solution from 2015 up to current date for
skid-steers-hammers system for demolition application in Peruvian market;
however, its price represents 20% of acquisition price, for that reason, it
is recommendable to start optimization research to reduce production costs. |
This adapter plate was
standardized to be used by the majority of brands which work with Atlas Copco
hammers and the serial production surpasses 500 units up to date with
reliable performance and having, as a result, lower warranty claims and side
effects over hydraulic hammers.
Figure 15. Adapter plate as final
product 4.
Conclusions Stress applied during the
demolition of hard road covers, pavement and asphalt, across the system
including skid steer-adapter plate-hydraulic hammer was identified as the
main concern of this study and the style of operation. For that reason, as
part of an optimized product development, training videos were developed to
improve operational skills. Complementary to
that, a warranty claim strategy was established to reestablish confidence in
the products and an exclusive supplier was appointed including a reliable
warranty response, which contributed to reintroducing the product reducing
the warranty claims of failures in hydraulic hammers to a 99% during the
following 12 months. There is space for
the optimization process because the safety factor obtained is higher than
7.95 and the difference percentage between static and dynamic results are
lower than 50%, and in the industry, a reference of 20% is used to obtain the
maximum resistance. However, the peaks of stress do not exceed the maximum
tensile yield stress of ASTM A36 carbon steel which was 250 MPa, and the
maximum compressive stress of ASTM A36 carbon steel was 152 MPa. The strategy
confirmed the use of the adapter plate as an element to protect the hammer
and skid-steer from deformation. The adapter plate
was demonstrated to act as a fuse protecting the hammer and skid steer arm,
confirming our hypothesis. Continual innovation is recommended to improve the
adaptor reliability and performance on job sites which will increase the
product’s reputation in the marketplace. |
|
Reference [1] N. Montes de Oca and S. Velut, “Energy modernisation and regional reorganisation
of the southern andes: The unexpected materialities of the southern peruvian
gas pipeline,” Journal of Alpine Research | Revue de géographie
alpine, pp. 1–16, 2022. [Online]. Available: https://doi.org/10.4000/rga.9465 [2] S. Maroye and A. Aerssens,
“Natural gas distribution network of lima and callao,
peru,” 2005. [Online]. Available: https://bit.ly/3A4d6ox [3] Atlas Copco, Safety and operating instructions Hydraulic breakers. Construction Tools PC AB, 2015. [Online]. Available: https://bit.ly/3u2XyxL [4] ITM, Manual de Seguridad y Bioseguridad para los Laboratorios
de Química del ITM. Instituto
Tecnológico Metropolitano,
2012. [Online]. Available: https://bit.ly/3btbhqS [5] T. Yalçin, “Design of a skid steer loader,” 2012. [Online]. Available: https://bit.ly/3ngsjv0 [6] L. Leung and G. P. Jenkins, “An economic evaluation of peru’s liquefied natural gas export policy,” vol. 74, pp. 643–654. [Online]. Available: https://doi.org/10.1016/j.enpol.2014.06.028 [7] Cálidda, “Instrucciones y recomendaciones técnicas para obras que impliquen trabajos sobre o cerca de instalaciones de gas natural.” [Online]. Available: https://bit.ly/3HWp19R [8] ——, “Guía del plan de prevención de daños (ppd),” 2022. [Online]. Available: https://bit.ly/3noe47r [9] Synthesis of
Dynamical Structure of the Hydraulic Breaker With a
Vibration-Free Handle, ser. International Design Engineering Technical
Conferences and Computers and Information in Engineering Conference, vol.
Volume 1: 21st Biennial Conference on Mechanical Vibration and Noise, Parts
A, B, and C, 09 2007. [Online]. Available: https://doi.org/10.1115/DETC2007-34667 [10] D. A. Ashcroft,
E. H. Priepke, and W. J. Sauber,
“Design and development of new generation skid steer loaders,” SAE
Transactions, vol. 103, pp. 252–258, 1994. [Online]. Available:
http://www.jstor.org/stable/44473342 |
[11] Wheeler CAT,
“Caterpillar performance handbook,” 2018. [Online]. Available: https:
//bit.ly/3u20ISq [12] CASE, “Skid
steer loadertier 4 interim certified,” 2013.
[Online]. Available: https://bit.ly/3bv1nVV [13] Epiroc, “Spare parts list hydraulic breakers sb 202,” 2022. [Online]. Available: https://bit.ly/3xY5PE4 [14] A.
Palomino-Valles, M. Tokumori-Wong, P.
Castro-Rangel, C. Raymundo-Ibañez, and F.
Dominguez, “TPM maintenance management model focused on reliability that
enables the increase of the availability of heavy equipment in the
construction sector,” IOP Conference Series: Materials Science and
Engineering, vol. 796, no. 1, p. 012008, 2020. [Online]. Available:
https: //doi.org/10.1088/1757-899x/796/1/012008 [15] J. Li, Y. Wang, K. Zhang, Z. Wang, and J. Lu, “Design and analysis of demolition robot arm based on finite element method,” Advances in Mechanical Engineering, vol. 11, no. 6, p. 1687814019853964, 2019. [Online]. Available: https://doi.org/10.1177/1687814019853964 [16] Y. Villa, “Esplicación práctica de uso de martillos hidráulicos,” 2014. [17] P. Preedawiphat, N. Mahayotsanun,
K. Sa-ngoen, M. Noipitak,
P. Tuengsook, S. Sucharitpwatskul,
and K. Dohda, “Mechanical investigations of astm a36 welded steels with stainless steel cladding,” Coatings,
vol. 10, no. 9, 2020. [Online]. Available: https://doi.org/10.3390/coatings10090844 [18] Matweb, “Matweb-astm a36 steel, bar,” 2015. [Online]. Available: https://bit.ly/3OJ0Uh2 [19] K.-l. Lu, W.-g.
Zhang, Y. Zhang, H. Huang, Y.-s. Chen, W.-y. Li, and C. Wang, “Crack analysis
of multi-plate intersection welded structure in port machinery using finite
element stress calculation and acoustic emission testing,” International
Journal of Hybrid Information Technology, vol. 7, no. 5, pp. 323–340,
2014. [Online]. Available: https://doi.org/10.14257/ijhit.2014.7.5.30 |