PD ISO/TS 13725:2021

What is PD ISO/TS 13725 about?  

PD ISO/TS 13725 is a document on hydraulic fluid power. PD ISO/TS 13725 specifies a method for the evaluation of the buckling load which: 

• Considers a geometric model of the hydraulic cylinder, meaning it does not treat the hydraulic cylinder as an equivalent column 
• Can be used for all types of cylinder mounting and rod end connection specified 
• Includes a factor of safety, k, to be set by the person performing the calculations and reported with the results of the calculations 
• Considers possible off-axis loading 
• Considers the weight of the hydraulic cylinder, meaning it does not neglect all transverse loads applied on the hydraulic cylinder 
• Can be implemented as a simple computer program 
• Considers the cylinder fully extended 

Note 1: PD ISO/TS 13725 is not developed for thin-walled cylinders, double-rods or plunger cylinders 

Note 2: PD ISO/TS 13725 is not developed for internal (rod) buckling 

Note 3: The friction of spherical bearings is not considered in PD ISO/TS 13725 

Who is PD ISO/TS 13725 for? 

PD ISO/TS 13725 on hydraulic fluid power is useful for: 

• Automobile companies 
• Aerospace organizations 
• Industries working with heavy machinery 
• Printing press 
• Industries manufacturing digging equipment 
• Furniture manufacturers 

Why should you use PD ISO/TS 13725?  

Hydraulic fluid power converts mechanical energy into fluid energy. Pressurized fluid is controlled and directed by valves into an actuator device. You can test the buckling load of a hydraulic cylinder using PD ISO/TS 13725. 

The method presented in this document has been developed to comply with the requirements formulated by ISO/TC 131.  PD ISO/TS 13725 determines the maximum allowable force, F max, that avoids reaching yield stress of the rod material, σ e, as well as buckling. 

PD ISO/TS 13725 discusses evaluating the buckling load of a hydraulic cylinder to execute the linear movement of the system by converting the hydraulic energy back to a mechanical movement. 

PD ISO/TS 13725 implementation on hydraulic fluid power modulates its function as it can overcome the pressure resulting from the mechanical loads on the system as well as the resistance to flow due to friction.  

What’s changed since the last update?  

PD ISO/TS 13725:2021 supersedes PD ISO/TS 13725:2016. PD ISO/TS 13725:2021 includes some technical changes with respect to PD ISO/TS 13725:2016. These include: 

• Formulae (18) and (27) have been corrected 
• The key to Figure A.1 has been corrected