Dowmload Mechanical Design Engineering Handbook by Peter R.N. Childs easily in PDF format for free.

Many attempts have been made at defining design. The word can be used as a verb or noun, describing the process and the outcome of design, respectively. Referring to design as a process, it can be considered to include all the activities of market assessment and user requirements, specification, concept generation and idea development, embodiment of details, risk mitigation, consideration of manufacture and production, and implementation.
Referring to design as a noun, the term is commonly used to describe an artifact such as a vehicle, item of fashion or other product, with the associated features and merits. This may include description or commentary on aesthetic, ergonomic, and technical features. In this book, an inclusive approach to design is used with consideration of a range of functionalities ranging from technical, aesthetic, social, economic, and latent.
Design is considered to be the process of conceiving, developing, and realizing products, artifacts, processes, systems, services, and experiences with the aim of fulfilling identified or perceived needs or desires typically working within defined or negotiated constraints. Engineering involves significant overlap with design and, indeed, it is often difficult to make a clear distinction.
A common distinction is the use of quantitative analysis in engineering to aid and inform the development, simulation, testing, and refinement of a system or product. Engineering can thus be considered to be the application of scientific and mathematic principles in combination with professional and domain knowledge, in order to design, develop, and deliver artifacts, products, and systems to realize a societal, commercial, or organization requirement or opportunity.
Mechanical engineering refers to the use of engineering processes to applications of a mechanical nature, typically involving moving components or energy processes. Mechanical engineering heavily relies on the engineering sciences of thermodynamics and mechanics, often integrated through design, in the development and refinement of a solution for a specific requirement.